Buck said the injury is improving, but he hasn't been able to test it out by running just yet.
"It's just a matter of trying to make sure it's pain free so it doesn't flare up again," he said. "I'll take a little precaution, but we just have to kind of base it off how it responds. I was able to run pretty hard the last day in Chicago [on Sunday]. I didn't sprint or anything, but did a pretty quick jog and did some multi-directional stuff in the outfield that held up pretty good."
Buck, who was hitting .216 in 74 at-bats but was flourishing as a pinch-hitter, will head out on a Minor League rehab assignment as soon as his body allows him to. But that's still down the road a bit.
"I'd like to get as many at-bats as I can to get my timing down," he said. "I would like to be able to produce and be comfortable up here, rather than rush just to get back."