Tyler Moore's stay at Triple-A Syracuse didn't last long.
The move on Haren, who is battling right shoulder inflammation, is retroactive to Sunday, the day after his most recent start in a disappointing season. Signed to a one-year, $13 million free agent deal in the offseason, Haren is 4-9 with a major league-worst 6.15 ERA in 15 starts.
Moore, a key contributor off the Nationals bench last season, has struggled to duplicate his 2012 numbers. In 38 games with Washington this season, he is hitting .158 with two homers and 13 RBIs. Moore hasn't fared much better at Triple-A, batting .178 with two homers and eight RBIs in 12 games.
In a post this morning, MASNsports.com's Dan Kolko looked at rookie Taylor Jordan, the Double-A Harrisburg pitcher who is expected to take Haren's spot in the rotation.
Why replace a pitcher with a hitter? It's possible the Nationals are merely cushioning themselves with an extra outfielder in case Jayson Werth's groin issue doesn't allow him to play tonight against the Diamondbacks.