Buying Tyler Chatwood by Mike Podhorzer December 11, 2017 Last week, the Cubs signed Tyler Chatwood, who has had the unfortunate luck of spending the majority of his Major League career pitching half his games in the most offense friendly home park. He has still managed to perform respectably given the circumstances, posting a 4.31 ERA and 95 ERA- (5% better than league average where lower is better) over his career, which includes 142 innings with the Angels in his 2011 debut. Now heading into his age 28 season, let’s see how the park factors compare between Wrigley Field and Coors Field and why the move makes him a prime sleeper. 2017 Park Factor Comparison Park Name R 1B 2B 3B HR GB FB LD K BB Wrigley Field 101 99 100 129 101 100 99 100 99 107 Coors Field 131 108 119 188 114 108 95 109 88 104 SOURCE: statcorner.com Statcorner presents park factors by batter-handedness, so I combined them based on the percentage hitters came to the plate from each side (59% and 41%). Obviously, compare most any park to Coors, and you’ll see a massive improvement in environment for a pitcher. Though it likely has a reputation for serious hitter friendlyness, Wrigley is barely better than neutral from a runs scored perspective. Coors, of course, is ridiculous. For every single hit type, Coors is significantly more favorable. Wrigley is just about neutral for all hit types except triples, which it majorly boosts. But Coors does so even more! Fewer hits of every kind should be a boon to Chatwood. Amazingly, even with the hit-boosting qualities of Coors Field, Chatwood has managed to post better than average BABIP marks over his last three seasons, and his just above .300 career mark is driven by inflated marks from his first three seasons. So perhaps he won’t see much of a benefit on the BABIP side versus previous seasons, but his projected BABIP would certainly be better since any projection system, including my own, couldn’t possibly forecast a below average BABIP for a Coors pitcher that isn’t generating a ton of fly ball and pop-ups (which Chatwood is not). One of the lesser considered aspects of moving parks is how the change might affect batted ball profiles. Wrigley is quite neutral for grounders, flies, and line drives, while Coors is far from it. It inflates both grounders and line drives and suppresses flies. Increasing grounders and line drives hampers BABIP, while reducing flies has the same effect. Chatwood hasn’t really had trouble with liners in his career, though I wonder how much Coors has increased his ground ball rate. A quick look finds that he has posted about a 58% GB% at Coors and 56% in away parks. Not a huge difference, so Chatwood has magically appeared to be immune from these types of effects. Another important difference in parks is the strikeout and walk rates. Coors dramatically reduces strikeouts, while Wrigley is about neutral. The more favorable strikeout environment is a potentially huge benefit for a pitcher who has never posted even a league average strikeout rate. In away parks, his strikeout rate rose from 16.1% to 17.4%, which still doesn’t push him into acceptable territory, but does finally match with the park effects. While the strikeout rate park effects are a positive for Chatwood, the change in walks is not, as Coors actually holds the advantage, boosting walks by a slightly smaller degree. He has posted a 10.1% walk rate at home and 11.2% in away parks. Most players perform better at home, so the gap isn’t out of line with what we would expect. The biggest takeaway here is the strikeout rate upside. He found a new gear on his fastball this year, boosting the pitch’s velocity nearly two miles per hour and maxing out at 99. That extra smoke likely contributed to all three of his secondary pitches generating SwStk% in the double digits. With solid SwStk% marks from his slider, curve ball, and changeup, including insanely how GB% rates from the latter two, he actually does have the repertoire that oozes upside. I love that he already owns that extreme ground ball rate, so moving to a much better home run park, his HR/FB rate should tumble back down toward league average, as he has suffered from severe gopheritis in 2014 and this season. That means that he shouldn’t be giving up a whole lot of long balls. Add to that the strikeout upside the park move could lead to and a pitch mix that could be strong, especially if he maintains that velocity boost, and you’re only left with hoping he finds some semblance of control. The good news is that control is the one skill that could suddenly appear out of nowhere, so I’m always willing to bet on improvement there than somewhere else. Though I certainly wouldn’t be aggressive on Chatwood in a 12-team mixed league, he’s an intriguing choice in deeper mixed and definitely NL-Only leagues. Coming off a 4.69 ERA, I don’t expect him to command too much draft day attention to drive up his price.