BALTIMORE -- Mike Napoli, who came out of Thursday's game in the bottom of the third inning with a combination of nausea and lightheadedness, remained unavailable Friday night as the Red Sox continued their weekend series with the Baltimore Orioles.
"He still has some symptoms of the illness,'' said John Farrell.
Mike Carp, who replaced Napoli at first base then homered in his first at-bat, was in the lineup again at first.
Farrell said Napoli couldn't trace the origin of the illness.
"That's probably the most puzzling thing,'' said Farrell. "Whether it was the humidity last night or....we've had a virus that has circulated through our clubhouse the last three weeks or so. It could be part of that. We're trying to get every test that we can get to get to the bottom of it and get information to Mike and get a better understanding of what he's dealing with.''
* After a 13-inning game Thursday night, Farrell made a couple of changes to the lineup.
David Ross got the start behind the plate, giving Jarrod Saltalamacchia a night off. Saltlamacchia caught Monday's 14-inning game at Tropicana Field, then caught Wednesday and Thursday's 13-inning game at Camden Yards.
Meanwhile, Jose Iglesias was at short. He's part of a rotation now to get some regular playing time at short and third.
Stephen Drew is just 1-for-17 on the current road trip, with his batting average dipped to .218 for the seaon. After a stretch that saw him hit .333 over a 10-game stretch, Drew is struggling with a .133 mark (4-for-30) in his last eight games.
Iglesias, entering Friday night, had a 14-game hitting streak at .444 (22-for-50).