Polanco was a late scratch Monday night. Manager Clint Hurdle said he thinks Polanco is showing some ''minimal improvement'' but wasn't sure if he'd be available off the bench.
In 18 games, Polanco is hitting .288 with one home run and seven RBIs. Sean Rodriguez started in place of Polanco, playing right field and batting eighth.
The Pirates might also be closer to getting right-hander Charlie Morton back in the rotation. Bothered by a right hip injury, Morton threw around 75 pitches during an outing Monday at extended spring training, and is scheduled to work seven innings in a rehab assignment Saturday at Single-A Bradenton.
Hurdle didn't know how many rehab starts Morton would need before returning to the Pirates.
''We're taking them one at a time,'' Hurdle said.