Dave Sheinin of the Washington Post has a story today on Rodrigo López, the savior of the Orioles' pitching staff so far this season. López has quietly contributed several exceptional performances in long relief, often bailing out aborted outings by the team's struggling young starters. He's held batters to a .138 average and a .348 OPS, allowing just 17 baserunners in 23 2/3 innings. Only three out of his eleven inherited runners have scored, and his ERA is an infinitesimal 0.38.
Over at the Baseball Prospectus site, Michael Wolverton's reliever evaluation tools place López as the current major-league leader in Adjusted Runs Prevented at 12.3. (López almost single-handedly has negated the atrocious work of Mike DeJean, who stands at -12.0 ARP.)
Wanna be startin' somethin'?
The obvious dilemma is this: with the starting rotation so inconsistent, should López stay in the bullpen or move back to the rotation, where he served most of 2002 (adeptly) and 2003 (badly)? The Orioles seem to want to keep him in his current role. From the Post article:
Eventually, the Orioles' brass believes, their starting pitching is going to improve, and when it does, the team believes Lopez can remain an integral part of the bullpen as a set-up man, especially given his effectiveness this year against right-handed hitters, who are batting only .094 (and slugging .113) against him this season.
I wouldn't pay too much attention to that bit about right-handed hitters. One, it's only been a month, and two, López has fared about the same against lefties and righties in his brief career.
To get a read on the best role for López, it might be good to examine his history. In 2002, López made the team as a non-roster invitee and was quite good out of the bullpen early on. Upon entering the rotation, he continued to pitch at a high level for a few months before fading late in the season. Still, he finished 15-9 with a 3.57 ERA, good enough to finish second in AL RoY voting.
In 2003, he was the Opening Day starter and eventually started 26 games, but his performance took a dive. He went on the disabled list twice, and his ERA ballooned to 5.82. Oddly, his K/9 and BB/9 rates were almost unchanged from 2002. But in 2003 he was hit hard, and in particular he gave up home runs at a markedly higher rate. Some people suggested that his arm was tired because he had pitched in the Mexican winter league before the season. But he pitched winter ball before this season, too, and he's shown no ill effects so far, so that explanation doesn't seem as credible now.
It is certainly possible that López is more suited, physically and psychologically, for relieving than he is for starting. If this proves true, then a long relief role is best for him. But the Orioles need to weigh what is best for the team. If the Birds' starters continue to pitch less than five innings per start—as they have done all too often lately—it is unlikely that the bullpen, López included, will keep pitching as well as it has so far, and the team as a whole will begin to suffer.
In this high-offense era, the main job of a starter is to eat up innings while keeping his team in the ballgame. Obviously, this involves a different mindset from relieving. A starter must learn to be economical with his pitches. This means he must throw a lot of strikes and not be afraid to let his fielders do some of the work. A starter who can last seven innings and give up three runs is more valuable than one who can go five innings and give up two runs, because asking the bullpen to cover four innings on a regular basis is just too much.
The Orioles' starters have failed to last into the seventh inning lately, and the biggest reason is that they have been walking too many batters. The control problems should eventually ebb as the young starters learn to locate their pitches more intelligently. But at some point, if things don't improve the Orioles will have to tug on the leash. If this three-innings-and-out trend continues for another month, I wouldn't mind seeing López shift to the rotation for a while, with the displaced starter moving to the bullpen to work on his control in long relief. This has already happened to an extent, as the Orioles have put Matt Riley in the bullpen for a couple of weeks to sort things out. Earl Weaver advocated using long relief as a low-pressure apprenticeship for young pitchers, and there's no reason to think that that approach wouldn't work today.
Credit López for not getting down on himself and letting his emotions adversely affect his performance. He did not accept his bullpen role easily at first, and he will continue to tell everyone who will listen that he prefers to start, but he has done everything the Orioles have asked and more.