Prove he is healthy, that is. He's been sidelined with injured knees since the end of May.
Tuesday represented the first day of the first baseman's latest attempt at baseball activity, with mixed results following running, batting practice and fielding.
"I thought it went decent," Sweeney said, "but the brain-trust didn't agree."
That higher power the A's veteran was referring to is head athletic trainer Stephen Sayles, who will play a significant role in deciding if Sweeney will start a rehab assignment in Sacramento or take the not-so-glamorous route to season-ending surgery.
"I think my plan is to run the bases and show these guys I can do it and then go to Sacramento," he said in the A's clubhouse before embarking on his activities.
Sweeney thinks Wednesday's workout will decide his fate, but the always upbeat veteran expressed much hope in the progress he made while in Arizona while the A's were on their 10-game road trip.
"It was still a bit painful when I was in Arizona, but it wasn't locking up or catching," he said. "I was just trying to build up leg strength. My doctor told me when I had the surgery that I would probably need a full eight weeks before I was ready for games.
"I just want to finish on my terms and get back on the field and help these guys win."
Sweeney underwent surgery on both knees on June 11 and has had one stint on the disabled list in each of the last seven seasons. What hurts more than the pain these days, though, is watching an A's team that entered Tuesday's game 3-21 over the last 24 contests.
"It's been depressing, and I'm sure the A's fans feel the same way I do," he said. "But it's not from a lack of effort. We've got a great group of men in here -- we're going to fight until the last day."
Jane Lee is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.