Nats positional preview: First base

It was no surprise when the Nationals opted not to bring free agent first baseman Adam LaRoche back. Ryan Zimmerman has battled injuries the past few years and the best option was to move him across the diamond to first base - especially with five years remaining on a $100 million extension he signed in 2012.

LaRoche produced 82 home runs and 269 RBIs in his four years in Washington, a stint that also included a Gold Glove in 2012. It's defense that figures to be the hardest for Zimmerman to make up for at first base in 2015. Zimmerman, 30, has only played 18 total innings at first base in the major leagues. But that doesn't seem to be keeping Nationals general manager Mike Rizzo up at night though.

"We feel the transformation from third baseman to first baseman will be smooth and seamless," Rizzo told MLB Network in December. "I've seen him take balls over there at first base and he glides around very nicely. He's got, obviously, great hands and great feet at third base, and we think that will translate into first base.

"We see him as a first baseman transformation a lot on the lines of Mark Teixeira when he went from third to first. We think he's going to be a Gold Glove-caliber first baseman and, of course, offensively he's one of the most consistent run-producers that we have."

Zimmerman, who's battled throwing issues at third base, knows the value of having a defensively skilled receiver across the diamond.

"I know how nice it is to have a good first baseman," Zimmerman said at NatsFest in December. "I've been lucky to play with a couple really good first basemen. Being on the other side of the field, it's comforting to know that you have a guy over there where, if you get it close, he's going to help you out a lot. And that's what I'm going to work to be because I know how nice that makes you feel when you're an infielder. But that's going to take a lot of work."

Nationals manager Matt Williams can add some assistance to the transition, having moved from third base to first base, where he started a dozen games in his career.

"There's plenty of people there to help," Zimmerman said. "I'm not too worried about it as much as I need to have a personal consultant or something like that. But Adam was great. Obviously, he's one of the best defensive first basemen I've ever seen play."

Will Zimmerman's body hold up throughout a campaign that's expected to last beyond the 162-game regular season schedule? He missed 101 of those games in 2014 with a torn right hamstring, a fractured thumb and shoulder issues. Zimmerman is no stranger to the disabled list, having missed numerous games throughout his career with hamstring and shoulder complications, as well as abdominal problems.

The battle to back up Zimmerman is an important one given his injury history. Tyler Moore has started 35 games at first base in his three major league seasons. The 28-year-old is out of options, meaning he must make the Nationals opening day roster or be exposed to waivers. In 2012, Moore earned a playoff roster spot after slashing .263/.327/.523 with 10 home runs and 29 RBIs in 75 games. However, his appearances in the majors have decreased the past year two years and his offensive production has followed. He struggled adjusting to inconsistent plate appearances in 2014 and hit just .231 with four home runs and 14 RBIs in only 91 at-bats. The right-handed hitting Moore was taken by the Nationals in the 16th round of the 2008 First-Year Player Draft. Moore's value also extends to his ability to play in the outfield, where he's appeared in 80 games for the Nats in the last three years.

In January, Rizzo signed Mike Carp to a minor league contract with an invitation to spring training. Carp appeared in 29 games at first base for Boston in 2013 and was an important utility option for the Red Sox during their run to a World Series championship. While splitting time mostly between left field and first base that year, Carp hit .296 with nine home runs, 43 RBIs and an .885 OPS.

However, his production submarined in 2014, when he managed just a .175 batting average with no homers and a .519 OPS over 149 plate appearances split between the Red Sox and Rangers. The 28-year-old has a career .254 batting average, 27 homers and 123 RBIs in 887 at-bats across six seasons with three clubs. Carp does provide an option as a left-handed bat coming off the bench should he make the roster in the spring.

Kevin Frandsen started six games for the Nationals at first base in 2014 and he's logged 376 innings at the position in the past four seasons in the majors. He returns in 2015 after hitting .259 with one home run with 17 RBIs last year.

Like Carp, Kila Ka'aihue was also signed to a minor league deal with an invitation to spring training. The 30-year-old Ka'aihue last spent time in the majors in 2012 with Oakland. He played the last year and a half in Japan, when he hit 25 home runs in 600 at-bats. In 126 games in parts of four seasons in the majors, Ka'aihue has batted .221 with 15 home runs and 46 RBIs.