TEMPE, Ariz. -- Scott Sizemore isn't afraid to acknowledge that he's had his fair share of bad luck, but perspective reminds him to also be grateful for it.

Grateful for the patience it's taught him, and for the added appreciation he's gained from it for a game that hasn't treated him kindly, at times, by way of injury.

Sizemore is one of the good guys, the type of guy you root for.

Everyone was rooting for him last spring when it seemed he was finally on his way to enjoying an uninterrupted season in the big leagues. It was going to be his breakout year, they all said.

Now, with that year having been wiped away because of a torn ACL in his left knee he suffered less than two hours into the team's first workouts last spring, everyone's rooting for him even more to come back from it and enjoy the kind of success he's always seemed destined to achieve.

"I hope all the bad is behind me, but you just never know," Sizemore said.

On Sunday, it was all about the good. With his biggest cheerleaders in the stands -- wife Brooke and newborn daughter Layla -- at Tempe Diablo Stadium, Sizemore was back in the infield in game action for the first time since September 2011. He was back at second base, his natural position, and looked quite at ease in the four-inning stint.

"He looks really good," manager Bob Melvin said. "I really did think it might take him awhile to settle in, but he's in the right place defensively, he's making all of the instinctive moves at second base that sometimes you forget about when you haven't been there in awhile."

It was Sizemore's first time at second base since May 2011, when he was asked to take on third-base duties upon being traded to the A's, who seemed to have finally found their long-term answer at a position that had turned into something of a revolving door since Eric Chavez's departure.

"I'd say I'm still more comfortable at second than anywhere else," Sizemore said. "It felt real good to get out there to just run around different situations, be in different places, have different responsibilities, all the stuff that you don't really practice until you're in a game. It felt good to be out in a game for the first time in awhile. It's nice to have your body do what it's used to doing."

The 28-year-old's body has taken one too many hard hits in such a short span.

Sizemore doesn't even consider his year-long rehab stint from the knee injury to be the most difficult point of his career. That time came at the end of 2009 and into 2010.

It was during the 2009 offseason when Sizemore was handed the immense task of replacing Tigers fan favorite Placido Polanco. That opportunity was offset when he broke his ankle in an Arizona Fall League game and opted to play through the pain the following spring. He did well enough to make the team as the starting second baseman but struggled to the tune of a .205 average and, by May, was optioned to Triple-A Toledo.

"Having to perform while not feeling 100 percent, it kind of leads you to doubt your ability," Sizemore said. "Being thrown into the big leagues when you're not at 100 percent, it was a little overwhelming because I didn't fully have confidence in my body. I didn't feel I was at my highest level of play, so it was a really, really tough year mentally."

But Sizemore "grew as a player and as a person through those hard times," he said, and that strength was what essentially got him through a blank 2012 season.

"I used that experience to be patient with myself and really let the healing process take its course and let the strength build up in my knee so that once I was ready to go my body I would be able to handle everything for a full season."

Sizemore believes he's at that point. But he still has plenty work to do, since his third-base job has since been taken by Josh Donaldson and a second-base job isn't certain, either, with Jemile Weeks and others in a battle for the starting role.

"Obviously, there are pretty high stakes for trying to make the team, and I know I need to go out there and perform," Sizemore said. "But at the same time, I need to be patient with myself and let things develop. But I feel good and, obviously, I'm not in midseason form, but ready to compete."

Back at home, crutches and rehab schedules have been replaced with a crib and feeding schedules for Layla, who has brought immense joy to the Sizemores, even through long nights.

"Luckily," Sizemore said, smiling, "I'm a deep sleeper."