John Jaso is minus his long, flowing hair, but what's more important is what's going on inside his newly clean-cut head.

"Brain stuff?" the A's catcher said when asked about his health before the A's FanFest on Saturday. "Yeah, it's all good up there."

Jaso missed the final two months of the 2013 season and the postseason with a concussion, but six weeks ago, specialist Dr. Micky Collins cleared him for all activity, no limitations.

Given the injury history and the A's trade of designated hitter Seth Smith this winter, Jaso, who led the team in on-base percentage last year, knows he could see time at DH this season. He said Saturday that he would prefer to catch. He's also played some first base and wouldn't mind getting work there this spring.