He has a lower slugging percentage than Esteban Loaiza, a lower on-base percentage than Josh Beckett and a lower batting average than Tomo Ohka, so Cristian Guzman, the starting shortstop for the entire existence of the Washington Nationals, is now being treated like a starting pitcher: He will receive a few days off between starts. At this point, what other choice do the Nationals have?

A 16-week ordeal came to that intersection of resignation and desperation yesterday afternoon when Nationals Manager Frank Robinson sat down Guzman and informed him he was being benched for the next few games. No longer content to give four at-bats per night to a hitter of historic futility, the Nationals must hope the mini-break succeeds in clearing Guzman's head and reviving his bat.

"It comes to a point where, for me, we're struggling and we need offense wherever we can get it," Robinson said of Guzman, who is hitting .189 after grounding out in a pinch-hit appearance last night. "You eliminate the weakest guy in your lineup."

The lineup the Nationals trotted out last night at RFK Stadium against the Colorado Rockies was a radical one, lacking not only Guzman but also veteran third baseman Vinny Castilla, whose achy left knee finally reached the point where he could no longer help the team. Instead of Guzman and Castilla, the left side of the Nationals' infield consisted of shortstop Jamey Carroll and third baseman Carlos Baerga.

Castilla acknowledged there have been days when he has wondered how he managed to drag himself out to third base, and he further acknowledged that he might have taken himself out of the lineup weeks ago if the Nationals were not in a playoff race.

"When the team is losing it's different," Castilla said. "You want to take care of [your injury]. But when you have a team like this, everybody's going out there [and playing] hurt and trying to help this team win."

It was their uncanny knack for winning close, low-scoring games in the first half of the season that convinced the Nationals they could afford to keep Guzman at shortstop despite offensive numbers that make him, statistically, the worst everyday player in the majors.

"If we were still winning, he would still be run out there," Robinson said. "Winning cures everything."

Since the all-star break, Guzman's numbers have continued to plummet, only now the rest of the team could not overcome it. The Nationals entered last night's game having lost six of their last seven games, putting them within a half-game of losing their hold on first place. Meantime, Guzman is 0 for 16 since the break, and 2 for his last 39 dating from late June.

"When we take batting practice, I feel great. I hit the ball good," he said yesterday. "But as soon as the game starts, I don't know what happens."

Few modern players have ever endured a slump like this. The numbers are horrifying. Aside from the .189 batting average, his OPS (on-base plus slugging) of .502 is more than 100 points lower than the next-worst figure in the majors -- Pittsburgh's Jack Wilson, at .613 -- among hitters with a qualifying number of plate appearances.

Guzman's stunning lack of offensive production (he has just 13 RBI in 270 at-bats) virtually defies modern comparisons. No qualifying hitter has batted below the Mendoza line (.200) for a full season since Ivan DeJesus of the Chicago Cubs in 1981.

And speaking of Mendoza -- as in Mario Mendoza, the light-hitting shortstop of the 1970s whose annual flirtation with the .200 mark eventually earned him title sponsorship of that line -- the poor fellow actually batted .215 for his career with an OPS of .507, both slightly better than Guzman in 2005.

Staff writer Les Carpenter contributed to this report.