Sean Doolittle secured the final three outs Saturday night and joined his teammates in their customary post-victory high-five line. That's a sight A's fans have come to expect and enjoy this season.

Doolittle then retreated to the clubhouse, where trainers put him through a series of tests after he felt pain in his right side and back. That's an unsettling sight for the A's as they head into the last five weeks of the regular season.

First, the essentials: Oakland took advantage of a late wild pitch to snatch a 2-1 victory over the Angels before a capacity crowd of 36,067 at the Coliseum. Jon Lester pitched masterfully for seven innings, Luke Gregerson sailed through the eighth, and Doolittle navigated the ninth as the A's climbed back into a first-place tie.

They and the Angels both have 34 games left, including eight against each other. Needless to say, the A's hope Doolittle stays healthy for this dash to the finish.

He felt a "grab" in his lower back on a pitch to Angels shortstop Erick Aybar. The pain returned on Doolittle's next pitch, but it subsided soon after Aybar grounded out to end the game.

Doolittle completed the mobility tests - mostly twisting and moving side to side - without trouble, which left him optimistic. He still had the area wrapped in ice as he spoke to reporters.

"It might have been a cramp or something," Doolittle said. "By the time I got off the field and got back up here (into the clubhouse), it had relaxed."

Asked if he were worried about the injury, he replied, "Not really. If I wasn't able to do what the trainers asked me to do, I wouldn't be as encouraged."

The A's obviously need Doolittle as they try to outlast the Angels and avoid the dreaded wild-card game. Saturday night's save was his 20th of the season; for another measure of his dominance, consider he now has five walks and 80 strikeouts.