Washington Nationals shortstop Cristian Guzman strained his left hamstring running out a bunt in the eighth inning of yesterday's 7-5 victory over the Pittsburgh Pirates, an injury that will almost certainly keep Guzman out of the weekend series in Chicago against the Cubs.

Though Guzman wasn't put on the disabled list, the Nationals made a series of injury-related moves after the game. The club placed outfielder Ryan Church -- still struggling with problems with his right rib cage and clavicle -- on the 15-day disabled list, retroactive to June 23, and recalled infielder Rick Short from Class AAA New Orleans.

"It just isn't getting any better," said Church, who could go on a rehabilitation assignment during the all-star break.

The Nationals optioned right-hander Travis Hughes to New Orleans to make room for lefty Joey Eischen, who will be activated today, and moved right-hander T.J. Tucker to the 60-day disabled list.

Hearing for Byrd Set

Officials from baseball and the players' union scheduled a hearing for next Wednesday in the case of outfielder Marlon Byrd, who is appealing a two-game suspension, union spokesman Greg Bouris said yesterday. Byrd was suspended for colliding with umpire Joe Brinkman after being ejected on June 4. . . . First baseman Nick Johnson, who missed his third straight game, received an anti-inflammatory injection, and it is possible he will play this weekend.