Nationals shortstop Cristian Guzman, the object of some scorn for much of the season at RFK Stadium, has visibly changed his approach at the plate recently, and the results are starting to come, albeit slowly.

"It looks like he has more of a plan when he goes up there," Manager Frank Robinson said. "He's not guessing, like he was earlier. He's taking much, much better swings."

Guzman is now hitting more off of his front foot, rather than putting all his weight back and then lunging forward at the ball. The approach is similar to how he hit in Minnesota, where he spent the first six years of his career, amassing a .266 average. Guzman went 1 for 3 with a double in last night's 3-2 loss to San Diego, but hit the ball hard three times. He is now 7 for his last 17. The tiny spurt raised his average to just .193, but some members of the organization were encouraged.

"I feel good," he said. "I think it's getting better."

Guzman, though, committed a key error in the ninth inning of Friday's loss, and booted another ball in the second inning last night.

Wilson Struggles in Field

Outfielder Preston Wilson, acquired in a trade with Colorado at the all-star break, was supposed to improve the Nationals defensively, but that hasn't been the case. Robinson started him in center field, but decided the team was better with Brad Wilkerson there. Last night, Wilson -- who says he is learning the angles in left -- misplayed a ball along the foul line in the second inning.

"I would prefer to be in center, definitely," Wilson said. . . .

Catcher Brian Schneider sat out for the fourth straight game because of bursitis in his right shoulder, but he said he felt ready to play. "They don't want me to play today, that's okay," he said. "I'm fine with that. I'm not mad or anything like that. . . . I think they're looking out for me, which I appreciate."

He went 2 for 2 Tuesday, which brought his average to .284, his highest since April 8. . . .

First base coach Don Buford had an injection in his back to relieve pain, and wasn't at the game last night. He was replaced by hitting coach Tom McCraw.