There's little question Anthony Rendon can slide right into the Nationals lineup and be a competent -- if not great -- major league player. He may not offer a lot of home runs or steals, but he has solid plate discipline and could produce a high OPS.
Rendon has one major problem, however: a playing time crunch. Once Ryan Zimmerman returns from his DL stint, there's little the Nats can do to keep Rendon in the lineup. It's the same quagmire faced by Evan Gattis owners, but with a less optimistic outlook -- Gattis will at least play from time to time at catcher (while possibly rotating in at first base and outfield). With a stacked Washington infield, Rendon, like fellow time-crunched teammate Tyler Moore, would be lucky to get five at-bats a week.
Still, without getting too glib -- these things tend to work themselves out. Zimmerman's injury may be re-aggravated in his rehab. Adam LaRoche or Danny Espinosa may get hurt. Zimmerman owners and those Fantasy players looking to solidify their corner infield spot for the next two weeks (Pedro Alvarez owners, perhaps?) may want to look into Rendon as a short-term alternative. While he may not last deep into May, he should be a decent option until then.