He has not yet gained clearance to play baseball, but Frank Thomas remains a viable target for the A's. The former White Sox star, who has missed most of the past two seasons, is making progress as he recovers from two different breaks in his left navicular bone (ankle), according to his agent, Arn Tellem. "It's all favorable,'' Tellem said about the results of recent X-rays and a bone scan. "The doctors are all optimistic, and I think the A's are waiting for Frank to be cleared later in the month.'' Oakland general manager Billy Beane said Thursday that he prefers not to comment on medical matters but added, "It's a situation we've been monitoring throughout the winter and one we'll continue to monitor.'' According to a source with a team that had initial interest in Thomas, the test results were not good enough for that club to renew its pursuit of the two-time Most Valuable Player. There's no indication so far that Thomas will be able to play regularly in 2006, the source said.