--2B Willie Harris was placed on the 15-day disabled list with a pulled left oblique muscle, one day after he hurt himself fouling off a pitch in Atlanta. Harris was hopeful the injury wasn't serious enough to require a DL stint, but the Nationals didn't want to take any chances. There's no timetable for his return. "It's a very delicate area," manager Manny Acta said.

--2B Anderson Hernandez was activated off the 15-day disabled list Monday, a couple of days before the Nationals originally planned. Hernandez, out since March 25 with a strained hamstring, played only seven innings in a rehab assignment at Class AAA Syracuse and was due to play back-to-back full games before returning. But after 2B Ronnie Belliard (strained back) and 2B Willie Harris (pulled oblique muscle) both went down with injuries, the Nationals needed a second baseman, so they activated Hernandez. Asked if his leg were 100 percent yet, Hernandez said: "I can't say 100 percent, but I'm good."

--SS Cristian Guzman enjoyed one of the best games of his career -- a 5-for-5 effort against the Phillies -- on Monday but departed on a sour note. Guzman strained his left hamstring on his final at-bat of the afternoon and had to be helped off the field. The veteran said he felt something pop both as he hit the ball and again as he rounded first, but he was hopeful the injury was not serious enough to keep him from playing within a few days. Guzman has been one of baseball's best hitters so far this season, having recording multiple hits in six of seven games while leading the NL with 16 total hits.

MEDICAL WATCH:

SS Cristian Guzman (strained left hamstring) left the April 13 game. He said he hoped to return within a few days.

2B Anderson Hernandez (strained left hamstring) went on the 15-day disabled list retroactive to March 27. He began a rehab assignment with Class AAA Syracuse on April 12, and he was activated April 13.

2B/OF Willie Harris (strained left oblique muscle) went on the 15-day disabled list April 13. There was no timetable for his return.

2B Ronnie Belliard (sore back) left the April 8 game and did not play April 10-13. He is day-to-day.

1B Dmitri Young (strained back and hip) went on the 15-day disabled list retroactive to April 1. Young, who has been working himself back into shape while trying to manage diabetes, will remain at extended spring training in Viera, Fla. The Nationals hope he'll be ready to go on a rehab assignment at some point in late April and perhaps return to the big-league roster soon after that.

RHP Terrell Young (inflamed right shoulder) went on the 15-day disabled list retroactive to March 27. He started a throwing program at extended spring training in early April.

LHP Matt Chico (Tommy John elbow surgery in July 2008) went on the 60-day disabled list March 28. He will miss at least the first half of the season.

ROTATION:

LHP John Lannan

LHP Scott Olsen

RHP Daniel Cabrera

RHP Shairon Martis

BULLPEN:

RHP Joel Hanrahan (closer)

LHP Joe Beimel

RHP Saul Rivera

RHP Steven Shell

RHP Julian Tavarez

RHP Mike Hinckley

LHP Wil Ledezma

CATCHERS:

Jesus Flores

Josh Bard

Wil Nieves

INFIELDERS:

1B Nick Johnson

2B Anderson Hernandez

SS Cristian Guzman

3B Ryan Zimmerman

INF Ronnie Belliard

INF Alberto Gonzalez

OUTFIELDERS:

LF Adam Dunn

CF Lastings Milledge

RF Austin Kearns

OF Elijah Dukes

OF Josh Willingham