"It's very day to day-ish right now," Cubs manager Dale Sveum said Saturday. "He's obviously pretty sore and pretty bruised up."
Jackson said that's his style -- to play without fear as he roams center field.
"That's the kind of player you want, but there does come the risk factor of injury when you do that," Sveum said. "That's why, with the last couple years with Carlos Gomez playing like that in Milwaukee, they're bound to get hurt. The speed they create and the running, whether it's diving on the bases when they're running, and the fearlessness they have of walls, sometimes it's just a matter of time before something happens.
"You don't take that away from anybody -- it's a gift and a good thing," Sveum said. "If he doesn't catch that ball last night, it's a whole 'nother ballgame."
Jackson was injured as he grabbed Andrew McCutchen's fly ball to end the sixth and strand two batters. The Cubs had a 7-0 lead at the time, and won, 12-2.