The A's continued to play their game of addition by subtraction Tuesday, adding a 9-5 win over the Angels to a streak of six successive victories, but losing second baseman Scott Sizemore in the process.

Sizemore, who missed all of last season following left ACL surgery, sprained his left knee in pursuit of a short fourth inning fly ball.

He will fly Wednesday morning to the Bay Area and have an MRI on the knee to determine the extent of the injury. He sounded as optimistic as someone with a long history of injury issues could.

"It just didn't feel right after that play; it started to tighten up,'' Sizemore said. "It was better to come out right then and be safe rather than sorry. Probably scar tissue (from the 2012 surgery breaking loose) is the best-case scenario.''

Manager Bob Melvin said the A's might make some kind of roster move Wednesday, but first they'd like to know Sizemore's status. The likeliest promotion would be Jemile Weeks from Triple-A Sacramento.

The A's already had to play the game without right fielder Josh Reddick, who sprained his right wrist in Sunday's series-ending win in Houston. Reddick isn't thought likely to miss much time, and Oakland can only hope the same is true for Sizemore.

Stealing some of their own 2012 thunder, the A's squandered an early 4-0 lead and were down 5-4 entering the seventh inning. John Jaso, who wasn't around for the A's repeated comebacks last year, stepped up as if he was an old hand at all this, mashing a top-of-the-wall three-run homer to give the A's the lead back.

"It was just a crazy game,'' Jaso said. "I didn't think it was going out. I thought it might fall on the warning track. But it was one of those wall-scrapers. It was a good lift for us, and it's the kind of thing that deadens the other team.''

If the Angels weren't deadened already, two batters later Brandon Moss, who'd delivered a two-run single in the first, capped the game's scoring with a two-run homer.

"We've got a lot of confidence going right now,'' Moss said. "We're 6-2, and that's much better than 2-6, but at the same time, it's still only eight games.''