There's no question of Butler's talent. Before the 2015 season, MLBPipeline named him the 35th-ranked overall prospect (No. 2 in the organization).
Butler has reduced his walk rate this season -- to 5.4 percent from 11.4 percent last year -- but he has been punished by a few mistake pitches each game. In his last five outings, he has given up eight homers and 27 runs over 23 1/3 innings.
"I'm not sure if it's a focus thing or a mechanical breakdown," Butler said. "But just realizing that even if you get an out, it may not have been a good pitch. I had a couple of those as well. They're pitches that are in the middle part of the zone. They had action, so they got hit fairly well, but they were hit on the ground, and guys were able to make plays."
Typically, pitchers are hit harder as the game goes on and batters see them several times. However, Butler has become more effective the second time through the order. Batters are hitting .323 against him the first time through the order and .250 the second time.
"With pitchers that are starters that become relievers, that's the separator: They're not able to sustain effectiveness three times through the order," Rockies manager Walt Weiss said. "For Eddie, his stuff is plus. You don't want to give up on that. We've seen him good as a starter. We're not there yet where we're going to give up on him as a starter."
Butler is a candidate for long relief when Chatwood returns. He is comfortable using his entire arsenal in relief instead of saving certain pitches for later in the outing, and his power stuff plays up in short stints. Opponents are hitting .259 with no walks in the first appearance against him as a reliever.
"I think that's been the biggest benefit is the fact that I can throw off-speed pitches early in the count," Butler said. "I don't have to throw a fastball where they're trying to jump on it. I can throw a curveball in there, a slider, or whatever it may be. Being able to get ahead multiple ways is a big benefit."
Ben Weinrib is a reporter for MLB.com based in Denver. This story was not subject to the approval of Major League Baseball or its clubs.