Trevor Bauer Debuts Thursday: What Should We Expect?

It's hard to know what to expect from Bauer, realistically. Of course, he's a first-round draft pick, #3 overall in the nation, and his minor-league numbers have been more or less excellent, both at Double-A and since his promotion to Triple-A Reno. Between those two levels, he has a 2.23 ERA over sixteen starts: in his 93 innings of work, he has struck out 116 batters, while walking 48 (likely the main knock on his performance). That's pretty damn good. But how might that translate to the majors? And what should we expect on Thursday?

Rookie seasons

I haven't yet had a chance to do a Reno/majors analysis for pitchers, like I did for hitter's stats a couple of weeks ago, but ESPN's Tristin Cockcroft has come out with a similar piece of work. He took a look at 16 prospects over the past five years, all of whom were in Baseball America's Top 100 at some point, and made eight starts in both the Pacific Coast League and the majors. The results were that the pitchers' ERAs increased by 1.13 runs, with home-runs particularly up, their rate increasing by 60%. When the adjustment is applied to Bauer's PCL stats, the expectation is:
Bauer: 3.98 ERA, 1.58 WHIP, 4.60 BB/9, 9.84 K/9

Cockcroft notes that some of those numbers are very, very close to those put up by Tim Lincecum - a name often referenced in the context of Bauer - during his first major-league season (4.00 ERA, 9.23 K/9). Of course, Timmeh was perhaps helped by AT&T Park, though his splits for that year actually result in a lower ERA on the road. Those numbers are perhaps a little disappointing for D-backs fans - that 3.98 ERA is exactly the number posted by all Arizona pitchers going into Tuesday's game against Atlanta, and also matches the NL average for starters thus far. It would, however, be an improvement on our starters' ERA, sitting at 4.09.

It's also pretty good for a rookie pitcher. Of the 29 such starters to have thrown 80+ innings in their first season since 2009, only eight have a sub-four ERA. That list includes the 34-year old "rookie" Kenshin Kawakami, as well as Barry Enright and Josh Collmenter, neither of whom are currently in a major-league rotation. Also, we have to take into account Bauer's age: he's only 21. A 3.98 ERA would be almost identical to the 3.97 ERA put up by Zack Greinke in his rookie season, as a 20-year-old in 2004.

Really, it's very, very rare for a rookie pitcher to arrive in the majors and be completely dominant out of the gate. Of the 213 starters have thrown 80+ innings in their first season since 1990, less than a dozen have struck out more than a batter per inning, as Bauer's projection above expects. If he reaches that 9.84 K/9, it would put him fifth, behind Kerry Wood, Mark Prior, Hideo Nomo and Cole Hamels - some pretty elite company - and just ahead of Yu Darvish, who has a 9.74 K-rate this season with the Rangers.


16 pitchers have made their major-league debut in an Arizona uniform as a starting pitcher. Here are the results of those outings, ordered by Game Score. Overall, the team has gone 9-7 in those contests, the starting pitchers posting a record of 6-5, with an ugly collective ERA of 5.54 in 79.2 innings per work - an average just shy of fine innings per debut start. However, that ERA is skewed by the presence of the likes of Daigle, who probably should not have been starting, and certainly isn't a good point of comparison for Bauer. [In case you're wondering, Brandon Webb debuted out of the bullpen: His first start would be #1: seven shutout innings on three hits, with 10 K's]

Rk Player Date Opp Rslt App,Dec IP H R ER BB SO HR Pit Str GSc
1 Geraldo Guzman 2000-07-06 HOU W 2-1 GS-8 ,W 8.0 4 1 1 1 3 0 93 61 72
2 Micah Owings 2007-04-06 WSN W 7-1 GS-5 ,W 5.0 1 0 0 3 6 0 96 54 68
3 Enrique Gonzalez 2006-05-28 CIN L 4-5 GS-6 6.0 3 1 1 1 4 1 86 53 65
4 John Patterson 2002-07-20 SDP W 7-1 GS-6 6.0 3 1 1 2 4 1 85 52 64
5 Jarrod Parker 2011-09-27 LAD W 7-6 GS-6 5.2 4 0 0 1 1 0 73 50 61
6 Barry Enright 2010-06-30 STL W 4-2 GS-5 ,W 5.0 4 1 1 4 5 0 101 55 56
7 Cesar Valdez 2010-05-03 HOU W 9-1 GS-5 ,W 5.0 5 1 1 3 2 0 96 59 52
8 Dustin Nippert 2005-09-08 PIT L 7-8 GS-5 5.0 5 3 3 2 2 0 70 48 45
9 Patrick Corbin 2012-04-30 MIA W 9-5 GS-6 ,W 5.2 8 3 3 3 6 1 99 61 44
10 Nelson Figueroa 2000-06-03 TEX L 3-4 GS-7 ,L 6.1 7 4 4 1 2 1 93 57 44
11 Bryan Augenstein 2009-05-13 CIN L 3-10 GS-7 ,L 6.1 8 5 5 2 3 0 95 64 38
12 Edgar Gonzalez 2003-06-01 SDP W 10-4 GS-6 ,W 5.2 10 3 3 3 4 1 101 61 38
13 Wade Miley 2011-08-20 ATL L 1-8 GS-5 ,L 4.0 7 5 5 2 5 1 76 52 31
14 Nick Bierbrodt 2001-06-07 LAD W 13-9 GS-2 2.0 5 6 6 3 3 1 66 39 22
15 Lance Cormier 2004-06-19 TBD L 4-11 GS-2 ,L 1.1 6 7 7 1 0 1 41 21 13
16 Casey Daigle 2004-04-09 STL L 6-13 GS-3 ,L 2.2 10 8 8 0 0 5 49 35 6

If we look at all debutants in the majors since the beginning of 2009, the picture is not radically different. Over those 125 games, the players' teams went 68-57, with the starters having a 40-39 record, and a median game score of fifty. The Nationals' Stephen Strasburg and Rays' Wade Davis are tied for the best-pitched games over that time, with game scores of 75. And if you're really looking for a stretch, the greatest debut in modern history, was Juan Marichal's complete-game one-hit shutout of the Phillies in 1960, with one walk and a dozen strikeouts, which rated a 96. Nice though that'd be, I'm not quite expecting a repeat from Bauer.

Basically, treat this article as the textual equivalent of a paper-bag to breathe into. Yes, it's very exciting to see one of our top prospects starting their first game for the team. However, I'd be happy if he delivers us a quality start, something managed by only 36% of debuting starters over the past three-plus major-league seasons. Anything beyond that will be icing on top of a very tasty cake.

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