Who's on first?

The Nationals have a right fielder (one who will cost them $126 million over the next seven years). They've got one of the best third basemen in the game. They've got a pair of young middle infielders who can grow together.

The Nats have both a veteran and two young catchers who can share the workload behind the plate. They've got a solid left fielder who could be traded (but a couple of backup options in case that happens). And they've got a center fielder who is going to get a chance to prove last year was an anomaly.

So what's still missing from this puzzle? Oh yeah, a first baseman.

Plain and simple, the Nationals don't have one. (For those still clamoring for Michael Morse, general manager Mike Rizzo made it clear once again yesterday that everyone's favorite part-time player is still "a backup plan" in case another first baseman isn't acquired.) Which means Rizzo essentially has three remaining options: Sign either Adam LaRoche or Derrek Lee or attempt to trade for a first baseman.

Let's deal with the last scenario first. A trade seems increasingly unlikely, based on the way Rizzo was talking yesterday following the Jayson Werth press conference. For one thing, trades cost players in return, and the Nats aren't really looking to fill one roster hole by creating another. And they almost surely would have to create a hole somewhere else because Rizzo wouldn't be looking for a stop-gap solution via trade. He would want a younger first baseman who would be around for a while.

"We're looking for a person we can grow with -- this year, next year, long-term -- in a trade," Rizzo said. "We wouldn't do a trade for a short-term [solution] because you're giving up a piece to get a piece."

In other words, the Nationals aren't about to trade Ian Desmond or Jordan Zimmermann to acquire James Loney from the Dodgers.

So one of the two remaining free agents appears to be the answer. And for a variety of reasons, LaRoche is the more attractive choice.

The Nationals prefer a left-handed hitter to break up all those right-handers they now have in the heart of their lineup (Desmond, Zimmerman, Werth, Willingham). They're not closing the door on getting a right-handed first baseman, but as manager Jim Riggleman said yesterday: "It's generally assumed that you'd like to have some left-handed hitting."

The Nats also are willing to give LaRoche, 31, a two-year contract. As Rizzo stated, he's not looking for a one-year stop-gap. This team, while by no means giving up on 2011, is realistically targeting 2012 as a potential "go-for-it" season. They don't want to be in this same position a year from now, scouring the market for a first baseman again.

If, however, the Nats can't land LaRoche (who is also being pursued by the Orioles) they may feel like they need to go with Lee, 35, on a one-year contract. It wouldn't be an ideal situation, but they'd try to make it work and then proceed accordingly down the road. (The Padres, it should be noted, are also looking for a first baseman and have been connected to Lee in recent days.)

Why hasn't something happened yet? Because Rizzo has insisted he's not going to be pressured into making a move before he's ready. The educated assumption here is that Rizzo has made LaRoche a two-year offer, LaRoche is holding out to see if someone will offer more (or if Rizzo will increase his offer) and the two sides are playing a little game of stand-off until then.

"I'm not going to describe it as urgency," Rizzo said. "We've been continually looking at our options there and discussing them with the players and their representatives. So we've had dialogue all along with several of our options. We're moving along in that direction."

And one of these days, perhaps soon, the Nationals will have a first baseman.