It's been a tough stretch for Adrian Houser. Since the All-Star break, he's made six starts, and he sports an unsightly 5.63 ERA. The Brewers have managed to win four of those six games, but Houser himself has posted a negative Win Probability Added figure in five of the six. He's getting hit much harder over that span than he had been previously. His ground-ball rate is down, so he's not getting the double play ball that helped him out of several jams in the first half. He's allowed 10 extra-base hits in the second half, after allowing just 14 in 11 first-half appearances.
On the other hand, Houser is also missing more bats since the break, and his walk rate is fine. He's allowed a substantially lower opponent OPS over these six starts than he did in the first half, even as his ERA has jumped. That brings the central question into focus: Is he cooked? Or has he just gotten unlucky?
The stakes of that question rise, not only as the season nears its conclusion, but with each start made by Robert Gasser in Triple A. Gasser sports a 3.81 ERA for Nashville, in what is (because of the microscopic automated strike zone and because of the very lively ball) a fairly extreme hitter's league. He's fanned 143 batters in 113 innings, and over his last four outings, he's run a 2.35 ERA and struck out 34 of the 95 batters he's faced.
Gasser is clearly the higher-upside hurler at this point in time, even accounting for the fact that he would have to adjust quickly to the big leagues under the pressure of a pennant race. The argument for keeping Houser in place leans more on what the downside of each looks like. Obviously, Houser is capable of getting blown up now and then. However, even in this bad stretch of six starts, he's pitched 32 innings. He only failed to complete five frames in one of them, and in fact, he's gone at least five in all but that one start since returning to the rotation in late June.
As the team's aforementioned 4-2 record in Houser's second half illustrates, a fifth starter doesn't need to dominate. Good teams just need that guy to keep them in games and avoid wearing out their bullpen. The wrinkle with this team, though, is that the offense has been so bad that it's hard to pin down what keeping them in the game means. Perhaps the explosion this weekend in Texas is a sign that all of that is changing, anyway, but if not, we need to account for the fact that four or five runs will often beat this team.
Gasser is the guy who can, if he adapts quickly and bears up under the stress of a September fight for the division title, give a low-scoring team a clear path to victory even on their worse days. He just comes with added volatility, and a higher risk of leaving the bullpen to clean up a mess. Houser's low-grade reliability is a better fit, if the offense starts playing up to its potential, but the team needs to make a decision between the two based on their own merits, not on the chances that the lineup has an extended hot streak in them.
There is another option, of course. The team could add Gasser to the rotation, without demoting Houser, thereby creating a six-man rotation. That would alleviate any concerns the team might have about Gasser's seasonal workload if he slotted into the rotation, and it might improve the chances that Brandon Woodruff, Freddy Peralta, and Wade Miley make it to the playoffs both healthy and fully effective. On the other hand, unless the Crew goes on a hot streak soon to create some separation between themselves and the Reds and Cubs, every game will be precious down the stretch. The team will be loath to risk losing a start for Corbin Burnes, or for Woodruff or Peralta, in the name of adding a couple by Gasser.
Gasser is 24, and he pitched 137 innings last year. He could make the rest of the starts down the stretch without compiling a worrisome total for the year. If the team believes he can withstand the challenge, they should give him a shot in the fifth place in the rotation. If Houser shows well Sunday in Texas, though, he could secure his spot the rest of the way.