Guillen says he feels much better thanks to taking antibiotics and the off-day that was scheduled for Tuesday.
"The day off really helped me a lot. I needed to rest. I feel good today," Guillen said. "Hopefully, I don't swing like a little girl like I was the last few days. I had the flu pretty bad. It's something I don't want to talk about. Opening Day, I felt horrible.
Guillen was better on the field on Wednesday. He went 2-for-5 against the Phillies and hit the game-winning home run against reliever Tim Worrell.
Injury report: Right-hander Tony Armas Jr. said that his right groin is much better. He strained the groin on March 27 against the Mets and was placed on the disabled list the next day.
Armas is scheduled to come off the DL on April 12, but Armas said he would most likely pitch in Minor League games before pitching in a big league one. Armas threw on the mound on Wednesday and will do it again on Thursday.
Center fielder Ryan Church missed his second consecutive game because of a sore right groin. Church said that he most likely will not play in Thursday afternoon's game against the Phillies because left-hander Randy Wolf is pitching.
Manager Frank Robinson also hinted that Church could remain be on the bench if outfielder Terrmel Sledge gets off to a good start. In the first game against the Phillies, Sledge went 1-for-4 and drove in three runs.
Getting work in: Backup catcher Gary Bennett was spotted working on catching fundamentals with bullpen catcher Bobby Natal, bench coach Eddie Rodriguez and third base coach Michael Huppert around 2 p.m. on Wednesday afternoon.
Bennett does these drills once during every series so he will not get rusty.
"As long as (starting catcher) Brian (Schneider) stays healthy, this is what I have to do to stay sharp," Bennett said. "I can't be sitting five or six days and not stay sharp."
Way back when: Former Senators player/manager Mickey Vernon threw out the first pitch before the Nationals played the Phillies on Wednesday evening.
Vernon, who lives 20 minutes from Citizens Bank Park, said he loved playing in Washington because he was able to meet a lot of politicians.
In fact, Vernon said one of his highlights was playing in front of presidents, who usually threw out the first pitch every Opening Day. The first president he saw do the honors was Franklin Roosevelt in 1939.
"(His aids) would drive him out on the field, and they would help him out of the car and put him in the (box seat)," Vernon said. "It's a privilege and an honor to play in front of presidents."
Vernon was one of the greatest first baseman in Senators history. He hit .286 with 172 home runs and 1,311 RBIs.
Stat of the day: The Nationals are the youngest team in the National League East at 29.07 years.
Did you know: Thanks to a ninth-inning pitch-hitting appearance on Monday against the Philles, Wil Cordero became the second player to have three separate stints with the Nationals/Expos.
Lenny Webster the first to play with the franchise three separate times.
Bill Ladson is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.