The Twins have a pretty impressive collection of currently active, home-grown MLB starters and former starters, all of whom have come up in the last decade (I’m leaving Santana out of this).  Kyle Gibson and possibly Anthony Swarzak are about to join this crew, so I thought I’d compare the currently active group to the up-and-comers to see how we might expect Gibson and Swarzak to perform in MLB based on the records of those who have come before them.

The tables below are pretty self-explanatory, showing a variety of stats for Twins-developed pitchers in the low minor leagues (A+ and below), high minor leagues (AA and AAA), and MLB.  All tables are sorted by the MLB leader in the respective statistic.

(FIP, for those who don't know, is a stat on the ERA scale that basically measures only rates of Ks, BBs, and HRs. Here I calculated it without HBP and IBB included, although those are typically part of the equation.)

As you would expect, as our pitchers have moved up the ladder to the majors, they’ve seen their stats decline.  On average, as compared to the high minors, the higher level of competition in MLB has knocked out more than a strikeout per 9 innings, edged up our guys’ walk rates, and almost doubled home-run rates by adding about half a homer per 9.  Not everyone follows the trend exactly, but there are pretty clear tendencies. No player in the group improved his FIP going from the high minors to MLB.

If Gibson followed the established Twins averages, his high-minors rates of 8 k/9, 2.1 bb/9, and 0.7 HR/9 would shift to about 6.8 k/9, 2.3 bb/9, and 1.2 HR/9.  That would give him a FIP of about 4.19 and you’d expect his ERA to be thereabouts as well.

The guy Gibson reminds me of most based on the stats is Scott Baker.  Baker’s K rate held up a little better than average in MLB, but his home-run rate took a beating and his overall shift from the minors to MLB was just about what you’d expect based on the team averages.  As it was with Baker, going just on the numbers you wouldn’t expect Gibson to turn into a true ace at the MLB level and scouting evaluations tend to agree.  Even Liriano and Garza, who had truly spectacular minor-league numbers, have had trouble performing like true aces at the MLB level.  But especially if you watched yesterday’s game, it is certainly easy to imagine worse things than having another Baker on the team.

Swarzak’s minor-league stats don’t suggest MLB success as a starter, although guys like Perkins, Duensing, and Blackburn provide some reason for hope.  Swarzak has also battled injuries to some extent and the “real Swarzak” might be a little better than his overall numbers suggest.  He’s unlikely to be an above-average MLB starter, but there are a lot of ways to contribute short of that.

With only 65 innings pitched above high A, I didn’t include Liam Hendriks above, but his overall MiLB rates of 8.8 K/9, 1.6 BB/9, and 0.3 HR/9 are very good, including going 8.4, 1.9, and 0.6 so far in AA, posting impressive mid-2.00s ERAs all the while.  Keeping that trend up would put him on the Gibson/Baker trajectory as well.