Tracy injured his groin during Saturday's 8-4 win against the Braves, when he hobbled into second following a pinch-hit double to break a 4-4 tie.
Tracy will fly to Philadelphia on Monday night and meet with a doctor Tuesday. Nationals manager Davey Johnson said Tracy had a lot of swelling in the area, but the skipper remained hopeful before the series opener in Miami that Tracy will not require surgery and that it's just a minor injury that will require treatment.
"Hopefully he won't need surgery," Johnson said. "He's another one [who's] valuable that we'll lose."
While Tracy landed on the 15-day DL, the Nationals moved outfielder Jayson Werth to the 60-day DL and selected the contract of outfielder Corey Brown from Triple-A Syracuse. In 48 games with the Chiefs, the left-handed Brown hit .297 with a .399 on-base percentage.
Tracy was Johnson's go-to left-handed hitter in late-game situations, and said with Tracy sidelined, either Brown or outfielder Roger Bernadina could fill that void.
"It's a good feeling to know they called me up to possibly help them out," Brown said. "Whatever they want me to do, whether it's coming in on defense or to pinch-run, hopefully I can help out in some way."