What if Jeff Locke and Rick Porcello were Traded for Each Other?

Jeff Locke and Rick Porcello are two pitchers with large gaps between their xFIP and ERA. How you value them depends largely on your faith in defense-independent pitching theory. Porcello sports a 3.27 xFIP but a 4.28 ERA. While his ERA- is a pedestrian 105, his xFIP- is an excellent 82. Porcello ranks 42nd among qualified pitchers in FIP WAR at 2.1 while his RA9 WAR ranks 57th at 1.5. Locke on the other hand has posted an unsightly 4.09 xFIP but a sparkling 2.47 ERA. His ERA- is a sterling 68 while his FIP- is 101. Based on FIP WAR, Locke ranks 58th at 1.4 while RA9 WAR puts him at 13th with 3.9. RA9 or “actual run prevention” says Locke is a real ace, the 5th best pitcher in his league, and Porcello is a slightly below average pitcher. xFIP says Porcello is an excellent pitcher, while Locke is merely a middling arm.

In order to understand the difference between Porcello and Locke, I dug deeper into their peripheral stats. Both have similar strikeout rates, with Locke at 18.1% and Porcello, who does not have the luxury of facing his own kind, at 17.8%. While Porcello has a 5.1% walk rate, Locke’s 11.3% is well above the MLB average of 8.0%. Porcello has been victimized by the long ball, as his 13.5% HR/FB rate is the highest since his rookie year, and two full points above his career average of 11.5%. On the other hand, Locke has managed to suppress home runs, as he has posted a 6.8% HR/FB rate. Some of this can be attributed to their respective home fields, as Comerica has a home run factor of 101, while PNC Park’s home run factor of 92 makes it the 3rd most difficult park to hit a home run. I would be wary of attributing any home run avoidance skills to Locke, as he allowed 9 home runs in 51 innings with the Pirates over 2011-12. ZiPs has him projected for a 9.9% HR/FB rate over the remainder of the season. Locke has also enjoyed an excellent LOB%, as his 82.2% is currently 5th in the majors among qualified starters while Porcello’s 69.5% is 74th. MLB average LOB% is 73.3. While Locke’s LOB% seems destined for regression (ZiPS projects it to be 69.0% ROS), a below-average LOB% may be part of Porcello’s profile, as his 69.5% is actually a career-best number.

However, the biggest reason for the ERA separation between Porcello and Locke is the defense behind them. Both Porcello and Locke are groundball pitchers, and their higher than average contact rates make them heavily dependent on their fielders. Porcello’s GB% of 57.2 is 2nd highest in the MLB, while Locke’s 53.3% is 8th highest. The Tigers have a team BABIP% against of .300 which ranks 6th highest in the MLB, while the Pirates are 2nd lowest at .271. Porcello’s BABIP of .313 is 13th highest among qualified starting pitchers, while Locke’s .261 is 75th. The following hand-picked GIFs illustrate the difference.

Porcello works with this:


(He doesn’t actually but I imagine the Tigers’ ballboy was inspired by their defense)

And Locke has this:

Jordy Mercer defense (From Forbes to Federal)

The difference in their defenses has contributed to the Tigers’ pitchers underachieving their xFIP, and the Pirates beating their xFIP. While the Tigers pitching staff has a league-best 3.38 xFIP, their team ERA is 6th-best at 3.57.  The Pirates have the 5th-best xFIP at 3.67, but a team ERA of 3.09 that leads the league by a wide margin, with the Braves next at 3.24. Put in other terms, the Tigers ERA is 106% of their team xFIP, while the Pirates ERA is 84% of their team ERA. Rick Porcello’s ERA is 131% of his xFIP, while Jeff Locke’s ERA is 60% of his xFIP.

After an analysis of the Locke and Porcello’s defense-independent stats and their defense-dependent stats, I thought it would be interesting to see what combining the best and worst of both worlds would be. The following chart is Porcello’s actual ERA and then his ERA calculated by multiplying his xFIP by the “Pirates Factor.”

ERA xFIP Pirates Factor “What if” ERA
4.28 3.27 0.84 2.75

And this chart shows Locke’s actual ERA and then his ERA calculated by multiplying his xFIP by the “Tigers Factor.”

ERA xFIP Tigers Factor “What if” ERA
2.47 4.09 1.06 4.34

I know, it’s a back-of-the-napkin calculation. xFIP doesn’t adjust for park and league factors, and Porcello’s LOB% probably wouldn’t jump to the Pirates’ team average of 77.1%.  Nevertheless,  its an interesting example of the difference that defense, park, league, and luck factors can have on a pitcher’s ERA over the course of a season. If Porcello pitched for the Pirates, he would probably be widely recognized as a very good pitcher, while if Locke pitched for the Tigers, he would most likely look average or worse. A change of scenery could have a big impact on either pitcher. But hey, who knows, maybe the recent acquisition of this guy can help Porcello look a little better.


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Chris Moran is a second-year law student, former college baseball player and assistant baseball coach at Washington University in St. Louis. He writes for Beyond the Box Score, Prospect Insider, DRaysBay, and sometimes other sites as well. Follow him on Twitter @hangingslurves

15 Responses to “What if Jeff Locke and Rick Porcello were Traded for Each Other?”

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  1. triple_r says:

    “the Pirates ERA is 84% of their team ERA”
    Assume you meant xFIP

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  2. This is good stuff, Chris. I’ve been driving the Porcello bandwagon forever based, in part, on what you present here. I write about him a lot over at my site, but I’ve never presented two opposite players like this to demonstrate the impact of context so neatly.

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    • chris.moran says:

      Thanks for the comment. I’ve been following Porcello for a while (a college teammate of mine had a couple at-bats against Porcello in high school). As you’ve noted on your site, he’s made some significant improvements this year (scrapping the slider and adding a curveball). But the improvements have shown up a lot more with regards to his DIPS numbers than his ERA. Even with his improved strikeout rate, batters put the ball in play above the league average against him, so he gets hurt by the Tigers’ defense more than his rotation mates. Scherzer, Verlander, Sanchez, and Fister have strikeout rates between 18.4-29.4% and the separation between their ERA and xFIP ranges from -.42 (Sanchez) to +.16 higher (Fister) a far cry from the +1.00 that Porcello features.

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  3. AD says:

    Doug Fister is a ground-ball pitcher too. Do you see his numbers skewing the same way as Porcello’s as a result of a Detroit defense of ill repute?

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    • chris.moran says:

      Both ZiPS and Steamer see Fister’s ERA going up slightly the rest of the way 3.83 and 3.67, respectively. Fister and Porcello have nearly the same peripherals.

      Fister: 3.34 xFIP, 18.4 K%, 4.2 BB%, 56.0 GB%, .311 BABIP%

      Porcello: 3.28 xFIP, 17.8 K%, 5.1 BB%, 57.2 GB%, .308 BABIP%

      Fister has been able to keep his ERA down to 3.50 compared to Porcello’s 4.28 mainly on the strength of a 10.5 HR/FB% which is 3 points better than Porcello’s and a 72.6 LOB% which is 3.1 points better than Porcello’s. I think they are almost equal value. I expect Iglesias will help them both, but I see their respective ERA creeping closer together. In my opinion both would be excellent pitchers on a team with a good to great infield defense.

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  4. Peter Moran says:

    Yeah, might as well just throw some dumb broad in there with a good defense an she’d look like Nolan Ryan!

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  5. Tigers Detractor says:

    Having watched Porcello in person a few times I can say that he performs better under bad batter conditions (cold inclement weather) and startlingly bad under better conditions (warm weather). Ive never noticed defense being tremendously important, because when hes getting hit, its rocket shots that no infielder would get. I have never seen Jeff Locke pitch, but I would imagine his success this year is because of the poor quality of the contact made on his pitches, which is evidenced by the high number of outs recorded on balls in play.

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  6. chris.moran says:

    Locke does have a higher IFFB% than Porcello, 9.7% to 4.5% but Porcello suffered through a .345 BABIP% last year even with a 15.8 IFFB%. I’d say the Pirates +17.4 UZR compared to the Tigers +2.5 UZR is the bigger difference maker. The year-to-year correlation for a pitchers’ line drive rate is very low, something like 0.11

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  7. KDL says:

    I love that in the 2nd GIF it really looks like the Pirates first baseman is starting to smile as he catches the throw.

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    • Chris moran says:

      You’re right, I didn’t notice that before. Lots of smiles going around the pirates infield, last I saw their opponents BABIP% on groundballs was under .200

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  8. chris moran says:

    Looks like Porcello’s luck didn’t improve in his start tonight. 5IP, 3ER, 6K, 2BB (1 intentional), 6/15 on balls in play. Game xFIP 2.68.

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  9. Ty says:

    Quick question, what is a better gauge for defense during the season, UZR or UZR/150?

    If I’m looking at the Royals as a team, in terms of runs saved by fielding, would it be better to look at UZR (they have saved 52.3 runs in 112 games), or UZR/150 (they are prorated to save 13.8 runs in 150 games)? I would think standard UZR is better to look at, as that is saving nearly 0.5 runs per game, compared to UZR/150, which only saves 0.1 runs per game (which is extremely miniscule and almost means that defense isn’t that important).

    If someone could answer my question that would be extremely helpful.

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    • Chris moran says:

      Use UZR for team defense it’s just the sum of each player’s defensive contributions. The impact of defense still pales in comparison to pitching or hitting but it’s not so insignificant that every team is +/- 1 defensive win of each other.

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