WASHINGTON -- The Nationals had been in the market this winter to add power and a left-handed bat.

Enter Joey Gallo.

The slugging outfielder/first baseman Gallo finalized a one-year deal with a mutual option for 2025 with the Nationals on Saturday. The deal is for $5 million, a source told MLB.com's Mark Feinsand, and also includes $1 million in performance bonuses.

"It was a good fit, just in terms of being able to go somewhere and get to play, and get a good opportunity to get at-bats and move around the field,¡± Gallo said in an introductory Zoom call on Monday. ¡°Also, I really like that team, too. It¡¯s always a fun group of guys to play against; it¡¯s always a challenging game when you play that team. I¡¯m very excited about that."

The Nationals had a vacancy at the starting first-base role after they designated Dominic Smith for assignment in November. Joey Meneses, who DH¡¯ed last season and has played first in the past, is expected to spend part of his time at first base this coming season. Gallo, 30, can help fill innings at both roles, as well as the outfield. Last season, the two-time Gold Glove Award winner made 36 starts at first base, 34 in left field, six in center field and six in right field with the Twins.

"The plan is for me to play some outfield, also play a little first base and kind of just help out where I need to help out," said Gallo, who spoke with manager Dave Martinez this past weekend. "I do take pride in being able to move around the field whenever and play any position, essentially. That¡¯s kind of what I told him, 'Wherever you need me to play, I can play. That¡¯s not a big deal, I¡¯m pretty versatile.'"

Offensively, Gallo was hit or miss in 2023. He showed off his light-tower power by belting 21 home runs in just 332 plate appearances, but his whiff and strikeout rates took a dip off his already historically high rates. He slashed .177/.301/.440 with a .741 OPS in 111 games.

The hope is that Gallo can return to the player he was a few years ago, when he hit 151 home runs across 573 games from 2017-21, including 38 or more three times in a five-season span while with the Rangers. Gallo has always hit for strikingly low averages, but he reached new extremes the past two seasons, hitting .168 while failing to hit for enough power (40 home runs in 237 games) to make up for it.

"For me, obviously, I am a slugger. I want to be more than that. I don¡¯t really like being known as just some 'strikeout/home run hitter' guy," Gallo said. "¡­ I want to get back to putting the ball in play more. I thought last year I struck out too much, and you¡¯ve got to put the ball in play to make things happen, too. So I think last year was tough with that."

But there¡¯s good news: Although his contact numbers are unimpressive, Gallo was still a net positive with the bat last season, posting a 104 wRC+. Gallo continued walking at an excellent pace (14.5 percent) and posted an elite hard-hit (52.9 percent) and barrel rate (19.3 percent). Any improvement in his bat-to-ball skills would help him go from average to good with the bat in a hurry.

"I don¡¯t look at average because I want to throw up if I do, so I¡¯ve got to relax on that one," Gallo said with a laugh. "For me, I¡¯m a walk guy. That¡¯s my singles a lot of times is getting on base, drawing walks, maybe having an eight-pitch at-bat. For me, it¡¯s on-base [percentage], OPS, things like that. Obviously, I would like the average to go up -- it¡¯s not like I¡¯m against hitting a higher average -- but it¡¯s just a little hard. But it¡¯s more of those stats for me, more of the stats for like a slugger."

Gallo was a bit below average in the field over the past two seasons, but from 2018-21, he was worth 7 Outs Above Average, so there¡¯s still a shot he can provide some value with the glove. He¡¯s also been a solid baserunner throughout his career, providing three baserunning runs in his career, per Statcast. FanGraphs has rated him as a positive contributor on the bases every year of his career.

There is a shot that Gallo¡¯s strong start to the 2023 season could be his true talent level, too. Gallo hurt his left hamstring in mid-May -- right around when he lost his home run swing -- and eventually had his season end in September due to a left foot injury.

The Nats designated prospect catcher Israel Pineda for assignment to clear space for Gallo on the 40-man roster. Gallo joins third baseman Nick Senzel and right-hander Dylan Floro as the Nationals¡¯ Major League offseason free-agent signings.