"Obviously, as you start to increase the workload, you have to see how his leg responds," Girardi said.
So far, so good, at least. Matsui took 45 swings off a tee Tuesday, and he reported nothing negative after the session.
"I felt pretty good," Matsui said through a team spokesman. "No pain. I hope to keep going in a positive direction."
If he continues in that direction, then Matsui should be able to avoid surgery, embark on a quick rehab assignment and be back with the Yankees after the All-Star break. But if the pain continues, then those plans might stall.
Matsui has been on the disabled list since June 27 with left knee inflammation, and he would have been eligible to return for Wednesday's game against the Rays. But when Matsui responded poorly to physical therapy and felt unable to take batting practice over the weekend, those plans changed. His timetable moved back past the All-Star break.
The Yankees will continue to proceed cautiously as they strengthen Matsui's leg, though Girardi insisted that Matsui is moving closer to game action.
"I don't know how long this next step is going to take," Girardi said. "But for him, my guess is it wouldn't be too long."
Anthony DiComo is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.