On Thursday against the Rangers, Hart started in the field for the first time this season. It marked his first appearance in the outfield since July 21, 2012, at Cincinnati. Two microfracture knee surgeries kept him out all of last season.
"I wasn't sure about fielding in an American League [game], but I figured here [in Miami]," Hart said. "It was good getting out there. I want to play the field more than not a lot of times. It's been baby steps. Keep me playing and not go backwards with my arms and legs. They've been really patient with me, and hopefully I can continue to progress health-wise so I can stay on the field more."
Mariners manager Lloyd McClendon penciled in Hart, who leads the club with four home runs, as the first baseman Friday. Over nine big league seasons, Hart has played 742 games in right field and 105 at first.
This spring, Hart worked in the outfield and told McClendon he was ready to give it a go after starting as DH in 10 of Seattle's first 14 games.
"It's a couple of things," McClendon said. "Obviously we keep him back in the lineup. I didn't want to put him back in the outfield back-to-back days. We also get a chance to give our first baseman [Justin Smoak] a day off because he hasn't missed a game. We want to make sure he stays strong as well. It's a combination of both things."
Hart hopes he can find his way into the starting lineup at least once more during the series.
"First is fine as long as I can get in there," Hart said. "It's a challenge for me. I like challenges."
Christina De Nicola is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.