Jordan Zimmermann has become an extremely reliable starter. In the last three years his ERA has been between 2.94 and 3.25, his WHIP has been between 1.09 and 1.17, and his strikeout rate has been between 18.6% and 19%. Those rate stats along with 12 wins in 2012 resulted in an ADP of 20-25 among starters for Zimmermann prior to the 2013 season. Despite posting similar rate stats, Zimmermann outperformed his 2013 ADP and finished as the 11th most valuable starter according to our valuations thanks to a jump up to 19 wins.

Zimmermann helped himself in the win category by pitching a little deeper into games. He made the same amount of starts in 2012 and 2013, but he threw 17.2 more innings in 2013. That works out to Zimm leaving the game with an average of 1.65 more outs per game. He also got a bit more help with run support as his run support per innings pitched was five runs compared to 4.7 in 2012. So he was leaving later in games and probably leaving with a lead more often. But those improvements aren’t huge and weren’t worth seven extra wins. When you also consider that we’ve only had 42 19+ win seasons in the last decade and that only six pitchers have had back to back 19+ win seasons in that time frame, it’s highly probable that Zimm’s win total will decline in 2014.

Because of the increased win total, Zimmermann is likely to be drafted as more of a top 15 starter as opposed to a top 25 starter like he was last year. But if his win total does indeed decrease, he’s going to have improve in other areas in order to produce a similar value next year and to be worthy of his draft day price. And given the consistency in the rate stats that was detailed above, an improvement in any of those areas may seem unlikely. But I think Zimmermann may have a proverbial ace up his sleeve.

To shift gears for a minute, let’s talk about changeups. Earlier this year, BP’s Harry Pavlidis published the results of his research into changeups. The results, to summarize quickly, were as follows:

- A big gap between fastball and changeup velocity will generally lead to more whiffs on the changeup.
- A smaller gap between fastball and changeup velocity will lead to fewer whiffs but more groundballs.
- Pitchers with elite fastball velocity and an at least decent gap to the changeup can get both whiffs and grounders with the change.
- Getting more sink with the change than the pitcher gets with the fastball can lead to both whiffs and grounders.

The average gap between fastball and changeup velocity for starters last year was 8.5 mph. So when you consider that Zimmermann’s gap was 6.7 mph last year, you would assume he fits into the category of getting more grounders with his change as opposed to getting more whiffs. And that’s backed up somewhat by the fact that his groundball rate went up last year when he threw changeups a little more often than he had at any point before. He also got grounders on a higher percentage of fastballs. But his changeup has induced grounders at a higher rate than any of his other pitches in each of the last two years, so doubling the rate at which he threw changeups had a lot to do with the increase in grounders.

Getting grounders at a higher rate than any other pitch wasn’t the only thing that Zimm’s changeup did better than his other pitches. He has also produced whiffs at the highest rate in each of the last two seasons with his changeup. That makes me think Zimmermann might fit into #3/4 above and be one of those special pitchers who can get whiffs and grounders with his changeup. If he is, then he should have excellent fastball velocity and a lot more sink with his changeup than he does with his fastball.

As it turns out, Zimmermann checks both of those boxes. Last year he was 8th among qualified starters in average fastball velocity. And as the charts below will show, his changeup definitely has more sink than his fastball does (and a little more fade since he really only uses it against left-handers).

There are quite a few things that have to happen for Zimmermann’s changeup to become this game-changing pitch that helps him improve his rate stats. His velocity has to hold, and velocity is a fickle thing. He has to continue to get more depth on his changeup. Those are things he has already shown he can do. But, most importantly, he has to start throwing the changeup more. He only threw it about 2% of the time in 2011 and 2012 before bumping that rate up to 4.7% last year. That increase is certainly a good sign, but it has to continue to rise. If you’re looking for a reason to be optimistic that it will, he threw his changeup more in the last two months of 2013. He still threw it only about 7% of the time, but at least it’s trending upward in the most recent sample.

The likelihood that Zimmerman’s win total will decrease is more likely than his changeup turning into a super pitch and helping his rate stats improve dramatically. At least immediately. But I do think he’s going to continue throwing the changeup more, and I do think it’s going to have a positive impact on his numbers. But the question is how much improvement will occur to offset the loss of fantasy value that will come along with fewer wins. Essentially Zimmermann will have to replace wins with more strikeouts. How many more strikeouts his changeup could produce is a mystery as is how many wins he needs to make up for. If he drops all the way back to 12, he’ll have no chance of mitigating that loss to an acceptable degree. But if he drops down to the 15-16 win range, there’s a chance he could make up for that.

There’s not much of a chance that Zimmermann has the upside of a top 10 fantasy starter. And if his win total drops dramtically and/or the changeup doesn’t become a bigger part of his repetoire, his downside is that he’s simply a top 25 starter as he was in 2012. So if his ADP ends up being in the 11-15 range, I think I might pass given that his downside seems a bit more plausible than him maintaining his value. But if he slips just outside the top 15 in starter ADP, you would be buying a little bit of upside with not a lot of downside. Which might be the ideal description of an early mid-round draft pick.