Bartolo Colon, Surgery, and Sample Size

Some interesting news came out this week regarding Bartolo Colon and his path back to the Major Leagues. Last spring he had stem cells surgically inserted into his elbow and shoulder, and this somewhat experimental procedure is now receiving a lot of notoriety due to Colon’s surprising success so far this season. I’m not a doctor and┬árealize that I have limited insight into medical procedures, so I’ll stay out of the debate about how effective this surgery may or may not be, but I do think that we need to keep in mind the reality of Colon’s performance when talking about whether this kind of procedure will be “the future of sports medicine”.

There’s no doubt that Colon has generated terrific results for the Yankees so far this year; his 2.81 xFIP is the lowest of any pitcher in the American League. He’s pounding his fastball for strikes and hitters are having problems doing anything with it. But if you look beyond just the raw results, there are some markers that indicate that this version of Colon isn’t all that different from prior versions.

Let’s start with his strikeout rate, which has been the lynchpin to his success so far. His 8.92 K/9 is way above his established career norms, and would represent his best mark since 2001. His swinging strike rate, however, is just 5.7%, lower than it was any of the last three seasons he took the hill. The only AL pitchers who are getting fewer swings and misses than Colon are Brad Penny, Ivan Nova, Tyler Chatwood, Wade Davis, Doug Fister, and Nick Blackburn. As a group, those guys have a collective K/9 of about 4.25, less than half of what Colon’s strikeout rate is.

As has been noted around the blogosphere, swinging strike rate has an extremely high correlation with strikeout rate (for obvious reasons), and is actually a better predictor of future K/9 than past K/9 is. Colon’s swinging strike rate is so low that it’s going to be nearly impossible for him to maintain this kind of strikeout rate going forward.

Whether he’s just been the beneficiary of some friendly strike zones or batters are so surprised that he’s throwing strikes that they forgot to swing does not really matter all that much – we have to expect that Colon won’t keep freezing hitters at the rate he has been, and his strikeout rate will probably return to something closer to his previously established norms.

Now, I know that it seems natural to think that Colon’s jump in called strikes could be due to this huge velocity spike he’s gotten since undergoing the surgery, but there’s only one problem – he hasn’t actually gotten a huge velocity spike. Despite all the talks about a “95 MPH fastball”, Colon’s average fastball speed this year is 91.7 MPH, essentially the same as it was in 2008 with the Red Sox. Sure, he’s hit 95 from time to time this year, but he’s always done that; his normal velocity is in the low-90s, though, just as it has been for most of his career.

His velocity is up from where it was in 2009, but that was a sample of less than 1,000 pitches and he was battling arm problems at the time. It’s not that surprising that a pitcher who had any kind of surgery after losing some velocity would get it back once he had recovered from his ailments, and that’s essentially what we see with Colon. He’s not throwing harder than he used to – he’s just back to what he was before.

And perhaps that’s the key point here. The miracle surgery narrative is being helped along by this perception that Colon was this awful, useless pitcher who couldn’t get Major League hitters out anymore, but that’s not what the data shows. He had one bad half-season in 2007 where his BABIP spiked to .357 and he posted a miserable 6.34 ERA, but his peripherals were good and he predictably rebounded to be a useful pitcher in both 2008 and 2009. Colon has never been lousy. This surgery didn’t make a bum into an ace because he was never a bum to begin with.

That doesn’t mean the surgeon is a fraud or that this technique won’t prove valuable in the long run. For one thing, Colon hasn’t broken down yet, so that’s new and different from previous years. If he manages to stay healthy all season, I’d imagine this won’t be the last time this surgery is performed, and we’ll eventually get a better idea of just how effective putting stem cells into a pitcher’s elbow can be. We just need to avoid getting caught up in the story of how this surgery has turned Colon into a frontline pitcher, because there’s a lot of evidence to say that, at the end of the day, he’s not that much different now than he was a few years ago.

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Dave is a co-founder of and contributes to the Wall Street Journal.

19 Responses to “Bartolo Colon, Surgery, and Sample Size”

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  1. Dave says:

    In the lead doctors own words of talks with Colon “He could not throw the ball without horrible pain”. Now he’s back routinely throwing upwards of 92 mph and not complaining of any pain. That is pretty amazing. I agree that this year’s durability will have a lot to with looking at this surgery further, I don’t think k/9 or swinging strike or anything should though. How well he pitches shouldn’t really matter, how hard he is throwing and how long he can do it for are really what should be monitored at this point.

    I am skeptical though of how much of the success of Colon coming back was due to the stem cell injection. Having worked in a stem cell research lab my knowledge of stem cells might be what some would call slightly above average. I realize stem cell’s growth and transformation into final tissues are greatly influenced by the tissues around them (secretions from those tissues actually) but this still seems a little like throwing paint at a canvas and hoping for art. I do think a more regimented rehab/training program could have played a significant role and nobody seems to talk about it. Much like Tommy John some pitchers see their velocity increase because they are simply in better pitching shape (arm strength, core strength, etc) than they ever were before. Bartolo has never been the pinnacle of fitness so looking after his arm and body better as part of this rehab may have had a significant effect and I feel it is being overlooked.

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    • descender says:

      Tendons/ligaments don’t really regrow… and certainly don’t repair themselves… unless you throw stem cells at them.

      I wouldn’t say it’s like throwing paint at a wall and expecting art, more like filling a leaky bucket with rubber cement.

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      • Cliff says:

        Say what? Tendons/ligaments do not repair themselves?? So no one ever recovers from a sprained ankle?

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    • Antonio Bananas says:

      Funny you should say that. When you sprain your ankle, your tendons are nearly permanently stretched out. Yes they do heal, however the likelihood of reinjury is greater because the joint isn’t as “tight”. Tendons heal, just not perfectly.

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  2. Temo says:

    What I don’t understand is how the Doctor that performed his surgery, who typically uses HGH in his treatment, had to go out of his way to NOT do so (or so he says he did, Colon was out of the league and not tested) just to treat a player.

    I think sports leagues need to take a closer look at their HGH policy. If it helps a player get treatment for an injury that will get him back on the field, and is typically used in non-athletic surgery, it seems perverse to deny the same treatment for the player.

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    • DavidCEisen says:

      Yeah, I don’t understand this either. I was under (maybe falsely) the impression that athletes can use banned substances under doctors orders.

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      • BillWallace says:

        If this were the case it would be awfully easy to find a doctor to prescribe any athlete anything he wanted to take.

        Come out to Cali and see how hard it is to get a cannibus card from an MD.

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      • DavidCEisen says:

        Exept the MLB has it’s own doctor’s on staff. I imagine there have to be ways that players are allowed to take banned substances for medic reasons. For example when Lester came back from cancer.

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    • Yirmiyahu says:

      You’re assuming that using HGH in this type of situation is a safe or effective treatment. Just because this doctor does it doesn’t mean it’s a good idea. I don’t believe the FDA or general American medical standards approve of the use of HGH for anything except growth disorders or hormone deficiencies.

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      • joshcohen says:

        true, but off-label use is probably more common than you’d think, especially in frontier medical specialties.

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      • Matt says:

        Just because the FDA doesn’t approve of it doesn’t mean that players shouldn’t be able to use it if their doctor thinks it will help them recover faster.

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    • Preston says:

      Does it even matter if he used HGH. He was in a different country and not on an MLB roster. To me it seems like FDA regulations and MLB rules really don’t come into play here.

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  3. phoenix2042 says:

    i think that the big thing for him right now is that he is getting a ton of called strikes with his two seamer. it has tons of movement and starts off the plate, ending up on the corner for a called strike. as long as he can keep on controlling it enough to do that, he can get a ton of called strikes and strike outs looking, but on the days he does not have that control, he gets pounded because the ball moves from the corner over the middle of the plate. that’s what happened against the rangers his last time out. i can’t find a statistic for called strike % or something like that on his fangraphs page, but i’m sure it’s above average for him, as that’s where his strike outs are coming from. i don’t know much about how predictive that is or how consistent, but that’s where his strike outs are coming, instead of swinging strikes.

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    • MonteroSmash says:

      Yes, that seems like a very great explanation on why Colon has lesser swinging percentage than his K/9 would indicate. I have watched all of Colon’s start this year, dating back to the Spring Training. He was still getting a lot of hitters struck out with his two seamer (even with much lower velocity; his 2 seamer was mostly 87~91mph then and was months before he cracked 96mph with 4 seam) And I would expect his average mph will creep up; his velocity definitely creeped up from the April (I remember being surprised about him hitting 94mph on the MLB gameday gun; some later appearances later, he was hitting 95mph, 96mph) so that will be another thing to observe.

      I hope Mr. Cameron gets to read both of our posts, I’d be curious on how thinks about this case. Yes, he does seem like he is up for regression (and I feel that he’d speak with more optimistic diction had Colon signed with, let’s say, Mariners, than Yankees) but he has this approach that pretty much freezes the hitter to be struck out (at least so far very consistently) so it will be interesting how it pans out. Who knows? Maybe hitters will learn how to cope with that 2 seamer and force Colon to show the different result. All I can say is that, as a Yankee fan, I’m glad that he is certainly playing up to the previous levels of excellence and if you are mad about it, all I can say to the haters is…

      U Mad?

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      • phoenix2042 says:

        his velocity has been on the rise, which is a good sign, but I am curious to see hitters adapt to the 2-seamer. the movement is great, and his control is what makes it devastating when he can tease it back over the corner. but i think hitters will catch on to that game pretty soon and be more aggressive, especially on fouling it off with two strikes. i wonder if colon can be as effective when he has to use his offspeed/breaking stuff more than 10% of the time if hitters foul off that put-away 2-seamer.

        i would still like a called strike % or something to back up what i’m seeing. i mean we have first pitch strike %, O- and Z- swing and contact %s, but i don’t see anything like that (though i could just be missing it). i think that called strike % should correlate with K rate, if not as well as swing strike % does. that could go a long way towards explaining the disparity between his swinging strikes and strike outs. it might also give us a better idea on whether or not he should be able to sustain 8+ K/9.

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      • phoenix2042 says:

        also, let’s not jump on dave cameron for his mariners affiliation and aversion to the yankees. i think he of all people has earned the right to be considered reliable when analyzing a player. everyone has their home team bias, but i’m pretty sure that he has a lot of practice recognizing and putting it aside when talking impartially about players. sure he might be a bit more enthusiastic about the Ms and the Yanks, but he doesn’t reach his conclusions based on that, instead he does his research and puts together an argument for the most likely scenario based on that, not on his own wishes. of course everyone has their unconscious biases, but i think they come out a bit more in team analysis or pertaining to specific players one likes or doesn’t like (like carson and colby lewis!).

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  4. RobMer says:

    I saw him pitch today for the first time this season. He hit 97 today against the Red Sox. He didn’t win, but he looked pretty darn good. I was skeptical Colon would provide much, but right now he looks more like a question of can he stay healthy. If he does, the Yankees picked up a pretty cheap #2 or #3 starter.

    Being the “same Colon” as in the past at age 38 and after missing a great deal of time (including all of last year) with shoulder and elbow issues, and then pitching like he has so far is quite extraordinary. I suspect there are other MLB athletes who will be calling this doctor.

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  5. Michael R says:

    All I can say is; what did people say when Greg Maddox developed his amazing 2 seam pitch. They said he was great, can the same be said about the way that a former Cy Young pitcher in Colon has used the pitch to his advantage?

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  6. noseeum says:

    I think a Glavine comparison is a good one here. If you are able to have mind-boggingly elite control, you can live by painting the corners. It’s just that so few pitchers can reliably get the ball within a couple of inches of their desired target to be successful using this tactic.

    The SwStr% only goes back to 2002, but Glavine was successful that year with a sub 8% SwStr%.

    The only thing for Colon is that he never lived by this tactic before, so I’ll remain skeptical that it’s sustainable until he keeps it up over the course of the entire season.

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