I can. Pulled hamstring is not that bad until you exert yourself. You can walk on them without remembering you're hurt. The second you try to run, you'll feel it. Depending on how bad it is, you can swing a bat.
He can't run the bases, but that is not as important if he hits a "double" to score somebody, stops at first and you just yank him. Especially if it's his back leg, it wouldn't surprise me at all if he could hit painless.