"Zack Greinke was scheduled to throw batting practice on the field Tuesday for the first time since being sidelined in the Milwaukee Brewers' spring camp with a cracked left rib.

When the weather didn't cooperate at PNC Park, the Brewers went to Plan B. Greinke pitched in simulated situations to hitters in an indoor batting cage, with balls and strikes being called.

When the 25-pitch session was done, manager Ron Roenicke was impressed.

"He threw the ball really well," said Roenicke. "He got after it.

"He's trying to come real fast now. I think (trainer) Roger (Caplinger) will have to look at that and make sure that we don't let him go full-go (too soon). That's what he'd like to do, so we have to watch that a little bit."

Roenicke said Greinke would pitch in another simulated session Friday and then probably go on a minor-league rehabilitation assignment to Class AAA Nashville. There's still a chance he will make his Brewers' debut before the end of the month.

"If he comes out tomorrow and he's not sore, I'll be pretty impressed because he wasn't holding back on anything," said Roenicke.

Greinke was a bit more tempered in his enthusiasm but said the session was worthwhile.

"It was all right," he said. "I think they're happy because I was throwing hard. I don't know if they're serious or just trying to be nice. Everyone told me that like a thousand times."