best pitching stat to follow in trade season
Homer Bailey is slated to take the mound for the A’s on Wednesday afternoon, his first start since coming over from the Royals this past weekend. Bailey joins Andrew Cashner (now of the Red Sox) on what will be a growing list of rotation starters for bad teams being acquired by contenders.
Do guys such as Bailey help “bolster” a contending rotation? This is something sports bettors (and Yankees fans) will be considering often in coming weeks. New faces in new places annually impact the championship chase. Bettors should know that the market sometimes has trouble pricing those new faces when backed up by better teams.
Bailey’s example is a tricky one. Cherry-picking stats can make the move look bright or dim.
Brilliant: Bailey’s ERA is in the mid-threes in June and July. Do that in the DH League with trick baseballs and you’re getting the job done. The Royals won four of his last six starts, and they’re barely even trying this season. Maybe Oakland just stole a lateblooming star who finally got things figured out.
Bonehead: Bailey doesn’t look as dangerous if you don’t focus on that hot recent run. And, even then, his ERA is 6.30 over his last two starts. You can’t count on him to pitch deep into games. He hasn’t completed six full innings in eight of his last 11 outings. A stunning home/road split (4.28 ERA in KC, 5.60 away) might also be a red flag.
Sharps don’t waste time building pundit-style narratives out of dataminded subsets. They focus on stats that do the best job of expressing skill sets.
VSiN has encouraged you often to look at xFIP (available at Fangraphs .com). That’s a “fielding independent” stat that focuses on what a pitcher has most control over (getting strikeouts, avoiding walks and home runs). No stat is perfect. This one captures “he is what he is” better than others. Check this out: Bailey in 2018: 6.09 ERA, 4.65 xFIP Bailey in 2019: 4.80 ERA, 4.62 xFIP Laughingstock in Cincinnati with record of 1-14 record one year, coveted by a contender the next. It’s the same
guy according to xFIP. Bailey’s just been pitching in better luck. You’ll find xFIP is a superior predictor of future ERA than ERA is itself.
Let’s answer the question about bolstering the rotation using xFIP. The four A’s regulars entering the new week: Frankie Montas 3.39, Chris Bassitt 4.80, Brett Anderson 4.97, and Mike Fiers 5.36. Fifth-spot fill-ins have largely struggled.
Clearly, Bailey is more likely to help rather than hurt. Though, that’s partly because Oakland’s rotation has been a weak point (the Yankees entered the new week with Domingo German 3.74, James Paxton 3.92, Masahiro Tanaka 4.19, CC Sabathia 4.83, and J.A. Happ 4.89).
After Oakland’s series with Seattle, 26 of its next 31 games will come against current contenders in either the AL or NL playoff races. A move had to be made. Good gamble.
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