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5/21/2013 12:41 A.M. ET

Pagan, Sandoval play despite battling flu

SAN FRANCISCO -- Giants center fielder Angel Pagan overcame his bout with the flu sufficiently enough to start Monday night's series opener against the Washington Nationals.

Manager Bruce Bochy indicated that Pagan, who left Sunday's game after five innings upon feeling ill, wasn't fully recovered. The Giants waited until Pagan took batting practice to determine whether he would remain in the lineup.

"This could be a gametime decision," Bochy said about 2 1/2 hours before the scheduled first pitch.

Third baseman Pablo Sandoval also caught the flu bug, but his ailment was mild.

"I play better when I'm sick," Sandoval told the Spanish-language blog Beisbol Por Gotas. "It's not going to stop me."

Infielder Nick Noonan, who was plowed into by Colorado's Carlos Gonzalez during a pickoff attempt Sunday, said that the right side of his neck and collarbone remained sore.

In another health-related development, right-hander Santiago Casilla revealed that he's wearing two different braces to cope with a cyst in his right knee. Casilla dons a light brace whenever he's not on the mound, then switches to a bulkier one to pitch -- which he had done only once before Monday since taking an eight-day break to rest the knee. The game brace, Casilla said, "is a little bit more uncomfortable."

Bullpen work uneven as starters struggle

SAN FRANCISCO -- The problems endured by the Giants' starting rotation have affected the bullpen, too.

The workload distribution has been uneven during the past week as manager Bruce Bochy has called on his middle relievers more than his setup men or closer Sergio Romo. Right-hander George Kontos and left-hander Jose Mijares made three and four appearances, respectively, during San Francisco's 1-5 trip, while Jeremy Affeldt, Javier Lopez and Romo each pitched once.

Bochy explained that he partly wanted to "protect" the likes of Affeldt and Romo, who had been pitching at a frequent rate until last week. Meanwhile, the starters' early disappearances have meant more work for Kontos and Mijares than is ideal.

As a result, fatigue has set in. Kontos has allowed six runs and 11 hits in 3 2/3 innings spanning his last three appearances. Mijares allowed two inherited runners to score in Sunday's sixth inning at Colorado and has allowed opponents to hit .311 off him.

Nats skipper familiar with pitching woes

SAN FRANCISCO -- Washington Nationals manager Davey Johnson can relate to the struggles of San Francisco's starting rotation, having guided some talented staffs himself.

Johnson's 1986 New York Mets, who won the World Series along with a staggering 108 regular-season games, had three starters -- Ron Darling, Dwight Gooden and Bob Ojeda -- finish with ERAs under 2.84. Two years later, his rotation of Darling, Gooden, Ojeda, David Cone and Sid Fernandez posted ERAs ranging from 2.22 to 3.25.

They rarely slumped. But when they did, Johnson found that pitch sequence tended to be a shortcoming.

"Sometimes your pitchers get in a rut," Johnson said before Monday's Giants-Nationals series opener. "Sometimes when you have really good command with one pitch, you use that pitch to set up all your other pitches and everybody gets to know it. You have to be able to go back and forth on setting up pitches to get guys out."

Johnson added that video equipment has eliminated surprises.

"With high-tech today, there ain't no secrets," Johnson said. "Everybody's got a video and everybody studies it, and there's somebody counting and tracking [pitches]. It's the same with hitters. If they have a weakness, opposing pitchers know how to get right at it."

Chris Haft is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.