PHOENIX -- Scott Sizemore was back in the A's lineup Thursday with his bruised left hand almost fully healed, and Jemile Weeks should return this weekend from a bruised right shoulder, Oakland manager Bob Melvin said Thursday.

After the pair of injuries put the A's second-base race on hold for a few days, the competition should heat up again in the next week. For Thursday's game against Seattle, Sizemore was penciled in at second, batting ninth.

Weeks received the majority of the club's starts at second base during the past two seasons, but following a strong rookie campaign in 2011, he regressed to a .221 batting average and just a .304 slugging percentage last season. As a result of that drop-off, Weeks said he doesn't feel like he's battling anyone but himself in regard to the starting job.

"I'm not out here battling any person," Weeks said. "Off the season I had last year, I'm just trying to better myself at this point. I'm bettering myself, and I feel like that will show in my game."

Weeks injured his shoulder during a double-play attempt last Friday against San Francisco, and he hasn't played since. He has been able to take ground balls and swing from the left side, but thus far it's been hitting right-handed and throwing that have caused the most trouble.

"You want to be out there on the field to show these guys what you can do and compete and get your feel before the season," Weeks said. "It's unfortunate for me that this happened, but the extra time certainly helps out."

For Sizemore, the only hindrance he's had as a result of the bruised hand is the follow through on his swing, when the torque in his arms is at its highest. The swelling has receded since he was hit by a pitch on Sunday, however, and Thursday marked the first time he was able to swing at full speed .

"I'm glad they gave me the rest," said Sizemore, who missed all of 2012 with a torn ACL. "It's a long season. Right now it's not the most important thing to push it and have something linger longer than it should."

The A's competition for second base remains open, and Melvin made sure to keep Jed Lowrie's name in the mix.

"It's a lot of moving pieces," Melvin said. "I'm not 100 percent sure what's going to be the dynamic. Lowrie? There are a lot of pieces we're still taking a look at through the spring."

Lowrie has played primarily shortstop in his five-year, big league career, and last season he played 93 games there for Houston. But with the Red Sox from 2008-11, he spent plenty of time at second and third and even mixed in some first base.

Young, Lowrie expected to give A's versatility

PHOENIX -- Chris Young played the field in 851 games during his seven-year tenure with the Arizona Diamondbacks. In all 851, he played center field.

Jed Lowrie may not be in exactly the same boat. He played all over the infield during his time with Boston from 2008-11. But he spent all of last season at shortstop for the Houston Astros.

So, if either of them felt out of sorts on Thursday -- when Lowrie played third base and Young played left field during a 7-3 win over the Mariners -- that's more than understandable.

Young couldn't recall ever making a play in left field at any level -- until Thursday, of course, when he saw three fly balls, making solid plays despite a nasty sun at Phoenix Municipal Stadium.

"When you've never been out there, you kind of feel naked," Young said. "You don't know if you're in the right place, and you feel like you're off line. I'm sure if I looked at a tape of it, it would look fine."

Where Young fits into a crowded Oakland outfield is still unknown. Josh Reddick, Yoenis Cespedes and Coco Crisp all would appear to have starting roles locked up, leaving Young as a designated hitter and spot starter in the outfield.

"The only way you're going to get better is through games," said Young, who came to Oakland in a three-way trade last October. "That's the only preparation that I've been doing. Wherever I'm put out there, I just try to learn as I go. I'm sure I'll make mistakes at some point, but that's the only way I'm going to figure it out."

Lowrie figures to see time all over the infield during the season, simply to help manager Bob Melvin create the best matchups offensively.

Lowrie, however, still feels like a shortstop, no matter where he is on the diamond.

"I'm going to take the majority of my ground balls at shortstop, just because I think you can get more work in at shortstop, more reactions, there's just more going on at shortstop," said Lowrie, who made plays on a couple of popups and a first-inning grounder and contributed a two-run homer. "Working there every day keeps me on top of my shortstop game. I've played there more than anyplace else in my career, so shortstop is where I'm most comfortable.

Melvin refused to refer to Young and Lowrie as "fill-ins" because of how much experience they bring to the table, and the fact that either or both of them could end up playing every day.

"It enables us to combat injuries," Melvin said, specifically addressing the outfield situation. "Yoenis was out for significant time last year. So was Coco. The formula -- I'm not sure yet. Once the season starts, and everybody's healthy [I'll know], but it's a good problem to have."

Melvin acknowledged that the all-purpose roles he will be asking Young and Lowrie to play are a much easier sell coming off a division title.

"That's what I've heard from them," Melvin said. "They just want to come in and keep things going in the direction that we're going and help the team win. There's definitely some pride involved when you have to go out there and play a different position."

Resop happy to be part of A's strong relief corps

PHOENIX -- When the A's were in the midst of their historic push for an American League West crown last September, Chris Resop was taking note 2,500 miles away -- specifically of Oakland's dominant bullpen.

A couple months later, the Pirates right-hander was dealt to Oakland for Minor Leaguer Zach Thornton, putting the seven-year veteran right in the mix.

"It's pretty much an honor," Resop said of being a part of the A's relief corps. "They trade for you to put you into their bullpen, knowing that they have one of the best bullpens. Obviously, they think highly of you and they respect what you do."

Resop avoided arbitration with Oakland by signing a $1.35 million contract in January. Last season, in 61 appearances during which he threw 72 2/3 innings, Resop posted a 3.91 ERA.

As for his new role in a loaded Oakland 'pen, he's still trying to figure that out.

"I have no idea," Resop said. "This bullpen is tremendous from top to bottom. I've had conversations with a few of the guys, and it's like, 'We don't even know.' Everybody in the bullpen can do pretty much anything here."

But there may be no one more multi-faceted than Resop, who, as a righty, shut down lefties last season to the tune of a .237 average. He also threw multiple innings 23 times in 2012.

"When you talk about our team and versatility, he's one of those guys," manager Bob Melvin said. We feel like he's a guy that can give you multiple innings. He gets left-handers out, he could set up for you if he had to and he's a bulldog. His focus and how he goes about his business on the mound has stood out."

In 2 2/3 innings this spring, Resop has yet to give up a run.

Worth noting

• With no game Wednesday, righties Jarrod Parker and Grant Balfour got their work in at the club's Minor League complex. Parker, who has made one start this spring, said his focus was specifically on his two-seam fastball and on putting hitters away after getting ahead in counts. He felt satisfied with both. Balfour, who hasn't pitched in a game since offseason knee surgery, had no setbacks.

• The A's are determining whether right-hander Michael Ynoa needs another session throwing to live hitters before he sees his first game action of the spring. Ynoa missed the first 10 days of camp while fighting chicken pox.

• Manager Bob Melvin on making sure his club doesn't get complacent after winning the 2012 division title: "Teams will look at us differently this year, but we can't look at ourselves any differently. Once you start to pat yourselves on the back a little bit, that's a distraction that we don't need."