Crain played catch on Tuesday after throwing another bullpen Monday. The most encouraging sign for the right-handed reliever is the lack of pain during the recovery process following the throwing sessions.
"The first few times I kind of threw, I was kind of sore, like I aggravated it," said Crain, who was placed on the disabled list retroactive to April 21. "Yesterday, I pushed it. I feel it when I throw off the mound, but it's more fighting through the scar tissue and getting it loosened up again and having it recover and feel even better the next time it gets better.
"So Wednesday is my big 'pen, my last 'pen. And I'll try to go as hard as I can 'pen-wise, and go on Friday and Sunday."
That Charlotte trip could return Crain to Chicago on Monday for the start of the two-game Detroit series.
"I felt better every day, and today was the best I felt so far," Crain said. "That's good because I threw a big 'pen yesterday."