The Associated Press

CHICAGO - Kerry Wood will have a bone scan today after he cut short a live batting practice session Sunday when he felt more discomfort in his right triceps.

The Chicago Cubs right-hander was put on the disabled list last Thursday, retroactive to May 12, and hoped to come off this Thursday and pitch Friday in Pittsburgh.

He left a start against the Dodgers on May 11 after two innings because of soreness in the triceps and has missed two starts since.

Wood warmed up in the bullpen Sunday and then went to the regular mound at Wrigley Field. But the batting practice session against real hitters lasted just eight pitches before Wood walked off the mound and into the dugout.

"He's not in any severe pain. We optimistically feel it's what we felt it was the other day. But since he didn't feel any better today and had a little discomfort, we're going to get the last test tomorrow and go from there," general manager Jim Hendry said.

DIAMONDBACKS: First baseman Richie Sexson went back on the 15-day disabled list with a left shoulder injury.

Sexson was activated Friday after missing 18 games with a partially dislocated shoulder sustained while checking his swing against Chicago on April 28.

He aggravated the injury on another check-swing Saturday. He'll return to Phoenix in the next few days to see a team doctor, Diamondbacks spokesman Mike Swanson said.

MARLINS: Florida right-hander A.J. Burnett passed another test in his comeback from reconstructive elbow surgery Sunday.

Pitching for Class-A Jupiter of the Florida State League, Burnett allowed two hits and one unearned run in four innings during a rehabilitation start.

His next outing is tentatively scheduled for Friday.