"Such a professional," Cubs manager Joe Maddon said Saturday morning of Chatwood. "This guy works very hard, cares about as much as you can care [and] has a great arm. To this point, it hasn't worked, but we anticipate it's going to."
Chatwood has 84 walks in 95 innings and a 4.98 ERA, though the Cubs have gone 11-8 in his starts this season. Still, he's walked a tightrope all year, leading to the change.
"I've been grinding for a while," Chatwood said. "It's just one thing that needs to click, and I need to do it consistently. From what I understand, feel good and get back in the rotation."
Chatwood was scheduled to start Wednesday in Pittsburgh, but that turn in the rotation will now belong to Hamels as he'll make his Cubs debut against the Pirates. He's scheduled to join the team Saturday afternoon and will be added to the roster Sunday.
Maddon didn't dismiss the idea of Chatwood returning to the rotation if the Cubs want to employ a sixth starter next month.
For now, the beneficiary of the move is lefty Mike Montgomery, who the Cubs are monitoring closely. His career high in innings is 130, achieved last season. He's at 87 now, after losing to the St. Louis Cardinals on Friday.
For Chatwood, the break from the rotation could prove fruitful as it may have been difficult for him to work on his complex mechanics while pitching every five days.
"It sounds illogical that he probably needs more work than less to work it through, but you never know," Maddon said.
Added Chatwood: "There's some stuff I need to work out. This will give me an opportunity to do that. ... I know I'm not pitching the way I can."