Windsor, Oakland's top pitching prospect, threw in a simulated game Saturday morning, but his outing was merely between-innings entertainment for the healthy crowd of media, players, coaches and A's executives who took in the successful four-inning simulated outing of rehabbing righty Rich Harden.

Harden, who has been on the disabled list with a strained elbow ligament since June 5 and has thrown four big-league innings since late April, when he was DL'd with a back strain, threw 60 pitches to a collection of A's reserves before the second game of a three-game series against the visiting White Sox.

Thus, pitching coach Curt Young said that barring a setback, Harden will be activated to start against the Indians on Wednesday or Thursday, with Thursday being most likely.

"The fact he got through it healthy was the No. 1 thing for me," Young said. "Him doing this, getting to 60 pitches without any discomfort, is what we were trying to accomplish."

Harden's fastball was routinely clocked between 88-92 mph, and he ran it up to 96 mph in his final frame, but Young and manager Ken Macha were far more impressed with Harden's command of his changeup.

"His changeup was very good," Macha said.

Added Young: "His best combination is fastball-change. When he has that going, that's enough."

Harden mixed in the occasional slider, and his velocity increased as he got deeper into the game. He didn't top 89 mph in his first inning, but nine of his 11 fastballs in the fourth inning were at 91 or higher.

"I felt pretty good out there," Harden said. "During the last inning, I was letting the ball go a little more. At the end, I just felt a lot better."

Harden will throw in the bullpen Monday, when he plans to throw his splitter full-bore for the first time. Backup catcher Adam Melhuse, one of the hitters who faced him, thought Harden looked ready to roll.

"Velocity-wise, he wasn't where we was before the injury, but it's tough to get your adrenaline going at 10:30 in the morning," Melhuse said. "He's not that far off. He'll probably throw a couple miles an hour faster in a game situation. He threw me a few changeups and they were outstanding.

"If they said he was game-ready, it wouldn't shock me."

Kotsay sits: Center fielder Mark Kotsay, who has been battling back spasms for much of the second half, was not in the starting lineup Saturday and probably won't start at least two of the four games against the Indians next week.

"He's a little stiff," Macha said, noting that he "held his breath" when Kotsay slid into third base on his RBI triple Friday night.

With seven of Oakland's final 10 games of the regular season to be played against the second-place Angels, Macha wants Kotsay as rested as possible by the time the Halos come to town for the first of those seven games next Friday night.

"Having him available on an every-other-day basis heading into the Anaheim series would be good," said the skipper.

Dribblers: Designated hitter Frank Thomas will be presented Sunday with the San Francisco chapter of the Baseball Writers' Association of America's Good Guy Award. Each year the local BBWAA members vote to honor one member of the A's and Giants for their cooperation and general professionalism in dealing with the media. ... Harden's first pitch over 90 mph Saturday was slammed off the wall in left-center field by catcher Jeremy Brown. A latter 96-mph heater was laced into left field, also by Brown. ... If Harden starts Thursday, lefty Barry Zito will be pushed back to Friday's opener against the Angels. That will set Zito up for a potential one-game playoff should the A's and Halos finish tied atop the American League West. That game would be played Monday, Oct. 2, at Anaheim, where the A's close out the regular season with a four-game set.

Coming up: A's righty Joe Blanton (15-11, 4.78 ERA) will take on White Sox righty Jose Contreras (13-7, 3.97 ERA) on Sunday in the series finale. The first pitch is set for 1:05 p.m. PT.