Even as Carlos Guillen ends his season-long stay on the disabled list and rejoins the Tigers today, it's possible that centerfielder Austin Jackson is now headed to the disabled list.

The Tigers announced after Friday night's game that Guillen has been activated. Manager Jim Leyland said Guillen will start today at second base and will play there at least somewhat regularly.

Jackson missed his fourth straight start Friday because of soreness in his left wrist. He was in the original starting lineup, then was scratched. The four-day All-Star break didn't clear up Jackson's problem.

"I'm a little concerned, obviously," Leyland said. "He didn't feel quite right. We're going to play it by ear for a couple of days and see what happens. But yes, there is some concern there."

If Jackson goes on the disabled list, the move would make room for the new fifth starting pitcher, who is due to join the team to pitch against Oakland on Wednesday night.

As it stands now, a position player who has been with the Tigers much of the season will have to come off the roster to make room for the new fifth starter.