What is the Nationals’ future at first - and where does Chris Marrero fit?

At the beginning of this season, the Nationals’ future (as in, the next couple years) at first base looked fairly settled. The team signed Adam LaRoche to a two-year deal with a mutual option for 2013, and planned to go forward with him as the replacement for Adam Dunn.

But a year after Dunn was playing his final games for the Nationals, the team’s future at the position doesn’t look nearly as settled. That’s mostly a good problem to have, though there are a few things to watch.

Here’s how things shake out at the moment: LaRoche is coming off shoulder surgery that the team hopes will have him ready for the start of spring training. Michael Morse, who played admirably at first base, is back in left field, where he struggled with his reads on several fly balls over the weekend. Chris Marrero is playing his first games in the majors, and has made a strong impression - he’s hitting .306, and drove in five runs in three games against the Astros, including two yesterday.

The Nationals have enough depth that Tyler Moore - who was their minor league Player of the Year last season and could have been again with 31 homers this year - will get a look in the outfield, as Byron Kerr reported Friday.

And there’s a chance the team could take a run at Albert Pujols or Prince Fielder, should either one get to free agency, though both sluggers would command a deal that would dwarf the $126 million package Jayson Werth got last December.

Setting those players aside for now, there’s plenty for the Nationals to figure out at first base. Do they think LaRoche can come back and be the same player next year? If not, does Morse go back to first, or does Marrero get a chance to win the job? If Jayson Werth can stick in center field and Bryce Harper can play right, Morse could stay in left, but he’s struggled defensively there so far. Marrero, though, is making the decision tough.

He isn’t hitting for power yet, but he’s shown the swing the Nationals always believed would take him to the big leagues. On Saturday, Marrero drove a tough 1-2 curveball up the middle for an RBI single and he blasted a double to the center field wall in the Nationals’ five-run third inning against Henry Sosa yesterday. He also had a sacrifice fly in the second inning, lofting a 1-1 pitch to right field.

“I definitely know that with a man on third, less than two outs and the open bag, the pitcher’s not going to give you too much to hit,” Marrero said. “If he does, you’ve just go to make sure you don’t miss it, trying to stay up the middle, not try to do too much. I got the run in and moved him over to third, so I’m happy about that.”

Marrero has already made two errors, and his defense has always been a question mark, though he showed marked improvement there this spring. If he continues to hit, the Nationals will have an interesting decision to make about where to start him next year; he seems to have mastered Triple-A Syracuse, posting an .825 OPS there this year.

There’s a chance the Nationals could try to trade LaRoche if Marrero makes a strong case heading into next spring, and if LaRoche is healthy, they could find a modest market for him. They’d also have Morse available if Marrero were to take the job and falter.

The guess here for now, though, is that LaRoche is at first next year and Morse is in left. Manager Davey Johnson has said he wants a more potent bench, and Marrero would give the Nationals a solid right-handed hitter for late-inning situations or days where LaRoche would be facing a tough left-hander. Don’t be surprised if Johnson lobbies to keep him, in part to build a better bench than what he’s had this season and in part to let him keep growing at the major league level.

He’s done enough so far to make the conversation interesting heading into next year.