ANAHEIM -- Chris Resop had played around with a sinker before, but he could never quite find a grip that felt right.

Then one day while throwing in Spring Training this year, the A's reliever was stopped by Bartolo Colon, who had been watching nearby. Colon simply moved Resop's hand on the baseball and told him to throw it.

And that's how Resop's sinker was born.

"The first one I threw felt comfortable," Resop said Thursday. "I had asked him in Spring Training how he threw his, and I never did anything about it after that until he showed me that day. I kind of ran with it and knew Spring Training was a good time to work on it, try to get a feel for it and trust it."

The sinker upped the veteran's repertoire to five pitches, all of which happen to be working quite well. Entering Thursday, the right-handed Resop had yet to give up a run through five innings spanning five appearances. His ERA during Spring Training, in nine outings, was also zero.

Many pitchers are better at verbally expressing themselves when things are going awry than when they're on cruise control. Resop is one of them.

"I can't really put a finger on it, on any one particular thing I'm doing," said Resop, in his eighth Major League season. "I'm just doing what I've always tried to do, get after guys and get ahead by throwing strikes early in the count, get outs early in the count."

Not only is Resop now equipped with a sinker that complements his four-seamer -- "I can go in to lefties and away to righties with that pitch and in to righties and away to lefties with the sinker," he explained -- but the 30-year-old is also throwing his cutter again, a pitch the Pirates took away from him last year. They thought he was relying on it too much and preferred his curveball anyway.

Around the same time, Resop suddenly found himself in a mopup role, losing setup responsibilities for a period that allowed him "to be confident I could do well in any situation."

That's served him well in the early going with his new team. Resop has pitched in every inning but the first three for the A's this year, excelling in each.

"An established role would be nice," he said, "but we don't get a win if we all don't do our jobs, no matter the inning."

Reddick rests again, could be used off bench

OAK@HOU: Reddick hurt chasing foul ball, exits game

ANAHEIM -- Josh Reddick asked his manager if his name was in the lineup on Thursday.

"Unless you can't read," Bob Melvin told him, playfully, "it says no Reddick."

Alas, the A's right fielder was out of the starting lineup in Anaheim for a third straight game after spraining his right wrist on Sunday, but he was expected to be a pinch-hit option for Melvin if all went well in batting practice.

Chris Young made his third consecutive start in right field against the Angels on Thursday in Reddick's stead.

"I know he feels good," Melvin said. "If all things went well, then he could potentially come off the bench. I do tend to err on the side of caution, but you never know how the game's going to play out."

Given Reddick's encouraging progression, there's a good chance he finds his name in the starting lineup for Friday's opener against Detroit at home.

"I was pretty worried," Melvin said. "Just the look of it was ugly, but it doesn't surprise me that he's responding this quick."

Sizemore's surgery to repair ACL set for Tuesday

OAK@LAA: Sizemore injures knee, leaves game in fourth

ANAHEIM -- A's second baseman Scott Sizemore, who tore the ACL in his left knee for the second time in as many years on Tuesday, will undergo surgery to repair it next week.

Sizemore will see Dr. James Andrews in Florida on Monday, and the renowned orthopedic surgeon will perform the procedure the following day.

Last year, Sizemore suffered the same injury in mid-February and was participating in full baseball activities by September. He should be on a similar schedule this time around, with rehab perhaps spilling into the offseason.

Should the infielder's rehab go smoothly, he should be at 100 percent by the start of Spring Training.

Between now and then, the A's will continue to rely on the second-base platoon of Eric Sogard and Andy Parrino, with several other options hanging around in Triple-A Sacramento, including Jemile Weeks and Grant Green. Rehabbing infielder Adam Rosales (intercostal strain) can also play the position.

Worth noting

• Parrino, promoted from Triple-A Sacramento on Wednesday to take Sizemore's roster spot, made his first start as for the A's on Thursday, getting the nod at second base. Parrino doubled in his first at-bat and came around to score the game's first run.