Chris Tillman: Good Pitcher, Not an Ace

Since Chris Tillman became a permanent member of the Baltimore Orioles rotation in July 2012, one could argue that he’s been the team’s best starting pitcher, albeit on a pitching staff that has been less than stellar during that time.   Since the 2012 season, Tillman has pitched about 500 innings, with an ERA of 3.42, which is better than any other Orioles starter by almost a half of a run.  A difference of a half run of ERA isn’t trivial over the course of the entire season.  Assuming 200 innings pitched, it adds up to 11 or 12 additional runs prevented.

Chris Tillman (photo via Keith Allison)

The topic of whether Chris Tillman is an ace isn’t a new one.  It’s been covered elsewhere, and has been covered here at Camden Depot as well.  Our own Jon Shepherd took on the topic in 2013 after receiving a reader email and then again towards the end of the 2014 season in a post he wrote for MASN.  In his previous posts, Jon first attempts to define an “ace”.  While he used slightly different methods, in both instances he arrived at the same place: in any given year the league has roughly 10 “aces”.  He then follows that discussion explaining why he believes that Chris Tillman does not qualify as an ace based on his previously defined designation.

While I in no way disagree with the conclusion of the two aforementioned articles, both of them generally used Fangraph’s version of WAR (and the components that contribute to it) as the basis for measuring whether Tillman should be considered an ace.  However, fWAR, FIP, and the statistics that reward them have never been Tillman’s strong suit.  He isn’t especially great at striking batters out (of qualified starting pitchers, he ranks 47^th in K% since 2012), limiting walks (ranked 82^nd in BB%), and doesn’t do a great job of keeping the ball in the yard (ranked 105^th in HR/9).  It’s no wonder that despite that 3.42 ERA mentioned earlier, Tillman has only been worth 5.6 fWAR since 2012, more than a win less than Wei-Yin Chen in only slightly less innings.

However, what Tillman has done well since 2012 is prevent runs, as noted by his 3.42 ERA during that time.  Run prevention plays a much bigger role in calculating Baseball-Reference’s version of WAR, so it’s not a surprise he’s been worth almost 3 more wins by their standards compared to Fangraphs over the same period of time.  It’s believed that certain pitchers have a skill that FIP is unable to capture, and will therefore post ERA’s that exceed their FIP on a regular basis (Matt Cain of the San Francisco Giants is the most recent example).  Since 2012, Tillman’s ERA has been better than his FIP by AT LEAST 0.67 runs each year (with a maximum difference of 1.32 runs during 2012).  Could Tillman be one of those rare pitchers that FIP just doesn’t understand?  It’s certainly possible, but it’s also probably too soon to tell (one could say the same for Miguel Gonzalez).

Hypothetically, let’s assume that Tillman does have the ability to regularly outperform his FIP.  If so, can he be considered an ace based solely on his ability to prevent runs?  In order to determine this, I looked at ERA+, which takes into account ballpark effects and the offensive environment of the era.  As Jon mentions in his articles, people can have many different views as to what constitutes an ace.  Because of that, I looked at the average, maximum, and minimum ERA+ values for the 10^th, 20^th, and 30^th best pitchers from 1961 to 2014.  

I then compared those values to Tillman’s ERA+ numbers since 2012 to see where Tillman fits in, if at all.

*From 2012, when Tillman only pitched 86 innings

It’s only two plus years of data for Tillman, but if you squint and use the most broad definition of what is considered to be an ace (one of the top 30 pitchers in baseball), one could make an argument that Chris Tillman is an ace when considering run prevention only (he’s obviously doesn’t fit in the more stringent ace categories).  However, I personally don’t consider a top 30 pitcher to be an ace (I’m in the “10-15 aces” camp), and even though Tillman could be viewed as a top 30 pitcher in baseball in terms of run prevention, the fact that he isn’t close to being a top 30 pitcher in terms of FIP and fWAR (as detailed in the previously linked to posts) further diminishes what little case Chris Tillman already has as an “ace”.

Just because Chris Tillman isn’t technically a traditional ace, does not mean he isn’t a good pitcher.  If you prefer FIP, he’s likely a number 3 or 4 pitcher on a good team.  If you’re more partial to strictly run prevention, he could probably be considered more of a number 2 or 3 pitcher.  Either way, he should provide decent value to the Orioles, even as he enters his arbitration years (Tillman and the Orioles avoided his first arbitration hearing last week by agreeing to a $4.315 million contract).  Of course, how much value Tillman provides will depend on whether he is in fact one of those rare pitchers who can consistently outperform his FIP, and remain on the fringes of being a “run prevention ace”.