Player’s View: The Best Stat to Evaluate Pitchers

I recently posed a question to 10 players. It was a question that doesn’t have an easy answer. Given the subjectivity involved, it doesn’t even have a right answer.

What is the best stat to evaluate pitchers?

Their responses are listed below in alphabetical order.


Brian Bannister, former Kansas City Royals righthander: “The most useful stat when you’re out there on the mound is your zone-contact percentage. I think it’s a huge contributor to your long-term success. The better the pitches are, and the more swings-and-misses in the zone, is what differentiates a pitcher with an ERA in the threes and a pitcher with an ERA over 4.00.

“It’s valuable to be able to throw pitches in the zone, to get swings and misses and a potential strikeout, without feeling you have to pitch around the zone. I think you’ll see a huge relationship between the elite pitchers in the league and their zone-contact percentage. Whether it’s Clayton Kershaw, Johan Santana, Matt Harvey, or R.A. Dickey, statistically they will outperform pitchers who really struggle in that category. Pitchers who can’t get swings and misses in the zone tend to rely more on luck, or tend to go through periods where they under-perform the league because of variance in balls in play.”

Craig Breslow, Boston Red Sox lefthander; “Good question. I feel that all the things that come to my head, I could find fault with. I would dismiss conventional stats, like wins and losses. But if I started to think about WHIP, hits become subjective to a certain degree. There’s a difference between base runners and the severity of base runners, or not normalizing for defensive factors like range. Of course, you can obviously look at fielding-independent stuff.

“I think I might go with strikeouts-per-nine-innings. Probably the most significant metric of dominance… if you consistently strike out guys at a pretty high rate, you’re usually going to be successful. Or maybe strikeouts-to-walks, because you don’t want a ton base runners. Strikeouts might be a really good predictor of future success. They obviously don’t allow for as much volatility as batting average on balls in play.”

Matt Cain, San Francisco Giants righthander: “You have to be lucky to get wins at times, because you can pitch well and go against another guy who pitches well. That’s a hard stat to judge pitchers on. ERA can be skewed too… you don’t really know what happened. There are times where I’ve definitely gone out there and, numbers-wise, maybe not given up any runs, but guys were hitting balls right at guys. Sometimes it’s hard to go solely on stats.

“I like innings pitched, because it shows a lot of what you’re trying to do in a game; you’re not thinking about striking guys out, you’re worried about trying to stay in the game a long time. You have to earn the respect of the manager to go out there and get that extra inning here or there.”

Jason Castro, Houston Astros catcher; “WHIP is a great stat for pitchers that a lot of people don’t think about immediately, since there are wins and losses, and ERA. Limiting guys from getting on base is a good place to start.”

Joba Chamberlain, New York Yankees righthander: “I’d probably have to say ERA. When you go back to Felix Hernandez, he was 11-11 going into his last six starts with a two-something ERA. I think he then won his last few decisions. He was obviously better than his record. Keeping your team in the game by not giving up many runs would be the biggest one for me. That’s ERA.

“As a reliever, your innings obviously ain’t as many, so if you give up a couple runs here and there, your ERA will become inflated. Inherited runners is probably more important. Hits allowed and strikeouts-per-innings-pitched are two more you look at.”

Brian Duensing, Minnesota Twins lefthander: “That’s a tough question. WHIP, maybe? If a guy’s WHIP is low, he’s obviously keeping teams down; he’s keeping them in check. With something like wins… a lot can go into getting a win, and a lot can go into a loss. ERA sometimes even gets skewed a little bit, because you might put guys on, but not be on the mound when they score. When I look at my own numbers, I do look at ERA, but I think WHIP is more important. If I’m giving up a lot of walks and hits, I’m obviously not doing my job as well as I should be.”

Jon Lester, Boston Red Sox lefthander: “I think they’re all important, although wins and losses get too much credit. You can only control what you’re doing. You can’t control how many runs your team scores for you, or a bullpen guy coming in and giving up runs. I’d say ERA and WHIP are probably the two you should look at.

“Strikeouts don’t matter. Strikeouts are a glorified stat. There are pitchers who don’t strike a lot of guys out having success. James Shields has had a couple of years with pretty good strikeout numbers, but for the most part he pitches to contact and goes deep into games. I think innings are another important stat. If you have a guy consistently going 190-210 innings a year… that’s important.”

Joe Mauer, Minnesota Twins catcher; “I think it could be different for different types of pitchers, and it depends on which pitcher you’re talking about. Is it a starter or a reliever. As far as starters, I think innings, a guy who can eat up a lot of innings, is real important. Opponents batting average is probably a pretty big stat. For a closer, opponents average would be big, too. ERA is important for both. But again, for a starter, I want him out there eating up as many innings as he can.”

Glen Perkins, Minnesota Twins lefthander; “I’d have to say FIP — fielding-independent pitching — if we’re talking advanced stats. If we’re talking more basic stuff, you could maybe say it’s your K-rate, either walks-per-strikeouts or strikeouts-per-nine. That feeds into FIP. Guys that strike out a lot of hitters are usually pretty darn good. But for someone who follows advanced statistics closely, it would have to be fielding-independent pitching.

“Wins matter, but not as a tool for evaluation. I don’t know if it’s the worst way to evaluate as pitcher, but it’s near the bottom. It just doesn’t tell you much at all. The other day, one of our guys threw four pitches and got a win. Earlier this year, I faced six guys, got two of them out, gave up a run, and got a win. It’s not like I pitched well. Wins is one of the worst ways to evaluate pitchers, but it is the best way to evaluate a team.”

C.C. Sabathia, New York Yankees lefthander: “I guess it would have to be ERA, keeping runs off the board. The way I look at it, innings pitched are big, too, pitching deep into games and giving your team a chance to win. And wins are big. You want to have the team win when you’re out there. I don’t think you can just discredit wins. But I guess I’d say ERA and innings pitched are the biggest.”



ERA: Two votes (Chamberlain, Lester 1/2, Sabathia 1/2)

FIP: One vote (Perkins)

IP: 2.5 votes (Cain, Mauer, Sabathia 1/2)

K/9: one vote (Breslow)

WHIP: 2.5 votes (Castro, Duensing, Lester 1/2)

Z-Contact%: one vote (Bannister)


Note: Thanks to Eno Sarris for procuring the responses from Matt Cain and Jason Castro.

David Laurila grew up in Michigan's Upper Peninsula and now writes about baseball from his home in Cambridge, Mass. He authored the Prospectus Q&A series at Baseball Prospectus from December 2006-May 2011 before being claimed off waivers by FanGraphs. He can be followed on Twitter @DavidLaurilaQA.

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Chris Headley
10 years ago

I’m pleasantly surprised by the number of players who are aware of advanced stats like FIP, and also find them useful. I went into this afraid half the answers were going to be win-loss record, but everyone seemed to realize it doesn’t mean anything in evaluating pitchers.

Dan Rozenson
10 years ago
Reply to  Chris Headley

Perkins and Bannister are well-versed in advanced metrics. I think they even read FanGraphs sometimes. (Hello, Glen and Brian!)

Hirohitahomerun already
10 years ago
Reply to  Chris Headley

I’ve got Breslow and Perkins on my first place team in a 10 team IQ League where the categories are (1) the player’s use of compound sentences in post game interview, (2) polysyllabic words, (3) number of time teammates refer to them as eggheads, and (4) compliments by Fangraphs commenters. I’m thinking of packaging them for Allen Craig, John Baker and Brennan Boesch.

10 years ago

Ill take my Joey Votto and Brandon McCarthy thankyouverymuch

10 years ago
Reply to  David

Don’t forget Ross Ohlendorf.