Keep both.
LaRoche shows no signs of slowing down. Consistent hitter, great fielder. Reminds me of Tino M. An attacking 1B, like Tino, Mattingly, Hernandez.
Morse? Why trade off a guy who can hit 30 homers a year and is also a good fielding 1B?
Depth is good. Consider the injuries the Nats had last year...every position except starting pitcher and 1B.