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5/7/2014 3:32 P.M. ET

Sore Reddick available off the bench

OAKLAND -- Initially expected to miss at least a handful of games with a sprained left ankle, Josh Reddick was considered available for Tuesday night's matchup with the Mariners.

Craig Gentry got the start in right field, but manager Bob Melvin said Reddick was "definitely an option" off the bench. Reddick was called on to pinch-hit on Monday, but Cespedes pinch-hit for him when the Mariners switched to a left-handed pitcher after Reddick was announced.

This coming just two days after Reddick suffered his injury running out of the box in Boston.

"He's a lot better today," said Melvin. "Actually I was surprised yesterday and probably got ahead of myself a little bit about how he felt, just from how he came out of the game the other day. Then he gets here yesterday and takes batting practice and felt pretty good."

Reddick is hitless in each of his last 14 at-bats, after compiling 16 hits in his previous 37.

Leon joins A's for doubleheader with Mariners

OAKLAND -- Right-hander Arnold Leon was activated by the A's for Wednesday's doubleheader against the Mariners, and he will make his big league debut if he appears in relief.

Right-hander Dan Straily gets the call for the first game. Drew Pomeranz will start the nightcap.

It will be Leon's first time in a big league uniform.

"I'm very excited," said Leon, who was in the A's clubhouse Tuesday. "First time in the big leagues, it's going to be a great moment. All my family's going to be here. It's going to be a special day."

The 25-year-old's parents are flying in from Mexico for the game, and his wife and 7-month-old son will also be in attendance. His father hasn't seen him pitch in person since 2012.

Purchased by the A's from Saltillo of the Mexican League in 2008, Leon is 2-1 with a 4.34 ERA in six starts for Triple-A Sacramento this year, his seventh in the organization and third since undergoing Tommy John surgery. He combined for 24 starts at Double-A and Triple-A last season after pitching in relief in 93 of his first 105 appearances.

The A's took notice of his progress in Spring Training, when he posted a 2.13 ERA and compiled 11 strikeouts in 12 2/3 innings.

"Good stuff," said Melvin. "We've seen it the last two springs. He really seemed like this spring he looked like he belonged. He was more confident throwing to big league hitters. I told him that at the end of spring and said, 'You've put yourself in position to be a viable option for us this year,' and here he is, and well deserved."

"I was expecting this from the beginning I signed with the Oakland A's, and I didn't know it was going to take so long," said Leon. "With Tommy John surgery, I feel a lot of personal success being healthy again. I'm very proud.

"I've been feeling pretty well. All of my pitches have been there, so I'm excited to pitch here."

Worth noting

• Rehabbing lefty Eric O'Flaherty (Tommy John surgery) threw a 30-pitch bullpen session in Oakland on Tuesday and is nearing the next step of facing hitters. Barring any setbacks, he could join the A's bullpen as soon as June.

• Infielder Jake Elmore remains with the A's rehabbing a strained left quad after reinjuring it last week.

Jane Lee is a reporter for MLB.com. Read her blog, Major Lee-ague, and follow her on Twitter @JaneMLB. This story was not subject to the approval of Major League Baseball or its clubs.