For now, Santiago will work on making adjustments while serving as the only lefty in the Angels' bullpen.
"Hopefully, things work out to where he gets his head right and we can get him back in the rotation sooner than later," Butcher said. "I'm sure it's obviously not something he wants to do, going to the bullpen, but I think just to kind of clear his mind out. ... He will still be in big situations coming out of the bullpen for us."
Command, Butcher said, has been the biggest issue troubling Santiago. He was yanked after 2 1/3 innings in his last start, which was the shortest outing of his season.
Santiago, who was acquired from the White Sox in a three-team deal in the offseason, has plenty of experience working out of the bullpen. The 26-year-old was used almost exclusively as a reliever for the White Sox during the 2012 season, and he made 11 appearances out of the 'pen in '13.
With the way he has been throwing the ball, Santiago assumed change was coming.
"Obviously I didn't want it to happen, but I was looking for something to happen the way it was going," Santiago said. "Hopefully this is the key. Go out and get that relief mentality. Go out and get one inning at a time, get back in there and hopefully finish the year in the rotation."
The Angels are hoping that's the case, too.
"He's done it in the past, and it seems like it has worked for him in the past," Butcher said about Santiago shuffling between the bullpen and rotation. "Take a little breather out of the bullpen, and hopefully this gets him back on track and gets him back focused to doing the things he needs to do to be a starter.
"We want him to get back to what he's capable of doing."
Chris Toman is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.