“I’m not going to miss the whole year,” Marrero said. “If you talk to people who had this injury, it takes a couple months to rehab from.

“Talking to my doc and the therapist, maybe I’m not going to be 100 percent by the start of spring training. It’s different for different people. I don’t know when exactly. I’m just keeping my body in shape, so when it does come time, I’m not out of shape. It’s just another speed bump.”

The Nationals had expected Marrero, a September call-up last year, to contend for a spot as their backup first baseman and as a power-hitting, right-handed option off the bench.

The Nationals need a reliable backup at first base with Adam LaRoche returning from the torn labrum in his left shoulder that ended his season after 45 games last season. LaRoche should be 100 percent by the start of spring training, but his recovery provides some uncertainty at the position.

Still, Marrero’s injury is not a huge blow to the Nationals, especially if he can return midway through the season or sooner. Most likely, the Nationals will replace Marrero with a bench player capable of playing first base. Michael Morse will begin the season as the Nationals’ left fielder, but if LaRoche’s shoulder falters, Morse could move back to first base, the position at which he had a breakout season.

Ken Rosenthal of FoxSports.com reported the Nationals have shown heavy interest in free agent Prince Fielder. Rosenthal is one of the best, but I can only pass along what I know: Everyone I’ve talked to with the Nats has indicated they will not be suitors for Fielder or Albert Pujols, and as of Monday night, that hadn’t changed.

After making his major league debut Aug. 27 last season, Marrero became the Nationals’ regular first baseman while Morse shifted to left field in preparation for this season. He hit .248/.274/.294 with no homers and 10 RBI in 117 plate appearances.

The hamstring tear gave Marrero the second major injury of his young career. In 2008, Marrero broke his ankle while playing at Class A Potomac and missed the final half of the season. Marrero seemed upbeat given his circumstances, focused on rehabbing and a relatively quick return.

“Any injury is not good,” Marrero said. “They’re all alike. I’m hoping I don’t have to miss too much time. I’m just going to have to get through it, get stronger.”

MLB.com first reported Marrero’s injury Monday night.