Mark McGwire is returning to baseball full time this season as the Cardinals' hitting instructor and Tony La Russa opened the possibility of him actually playing again. "If we're in contention, we'll put him on the roster Aug. 31. It's a nice little dream," said La Russa. He would be used as a pinch hitter for the postseason. "Is it likely? Probably not. I don't think it's a zero possibility. The point is, you'll see him in spring training. He won't be leaning on the batting cage chatting it up. He'll work his (butt) off, and hitters will be thrilled he's there helping them." McGwire last played in 2001.