Coach Steve Spagnuolo would not say how many players had the illness but said five or six players had flu-like symptoms, and added that other players had reported symptoms the last few weeks. He anticipated the Rams would return to practice on Friday with a workout that will incorporate some of the elements missed on Thursday.
"It's really more of a precaution than anything," Spagnuolo said. "We're checking everybody, we're just being careful."
Players were seen driving away from Rams Park shortly before noon after consulting with medical staff. Team spokesman Ted Crews said many players received medication before leaving.
"If there was one [player], we'd have to be careful because these guys are around each other all the time," Spagnuolo said. "I think it was the right thing to do."
Two players, quarterback Kyle Boller and center Jason Brown, missed practice Wednesday and Spagnuolo said both players had flu-like symptoms. Spagnuolo first reported Brown's illness on Monday, but Brown was back with the team Thursday and had been expected to practice before the team decided to send players home.
Spagnuolo said he didn't know whether Boller had been at Rams Park on Thursday. He was short on specifics regarding other affected players, saying "all the names are running together."
"I don't want to throw out a name and be wrong," Spagnuolo said. "The important thing is we don't want anybody else to get sick. The important thing is to handle it right, send everybody home."
Spagnuolo said coaches might leave Rams Park, too, after consulting with medical personnel.
Spagnuolo said the Rams became aware of the situation about 8:30 or 9 a.m., then held a team meeting after consulting with medical personnel and deciding on a course of action.
"There was no panic here," Spagnuolo said. "We took our time."
The Rams (1-12) host the Texans (6-7) this Sunday. Spagnuolo thought it a stretch that the game might be jeopardized.
"Don't send me down that direction," he said. "I'm very hopeful that by tomorrow, even if there's a couple of guys that have to be away from it, that we've taken the right steps and we'll be OK."
In early October, Texans rookie tight end Anthony Hill was hospitalized with swine flu in the first confirmed case in an NFL player this season. Other players around the league were also sidelined with flu-like symptoms.
The Texans were sympathetic to the Rams' plight.
"That's something that has been going around," wide receiver Andre Johnson said. "I think we'll be fine because we've already had our fair share of it around here, so I'm not really worried about it."
The nation's supply of swine flu vaccine is expected to reach 100 million doses this week, clearing the way for everyone to be protected, not just those considered at high risk. The 2009 H1N1 strain sickens younger people more frequently than the over-65 population who are seasonal flu's main victims.
Through mid-November, about one in six Americans have caught the new H1N1 flu, and about 10,000 have died, the Centers for Disease Control and Prevention said.
The new swine flu seems no more deadly than regular winter flu, which every year kills 36,000 Americans and hospitalizes 200,000.
Earlier this year, the NHL's Calgary Flames were criticized when players and their families received the swine flu vaccine while thousands of other people waited in lines that stretched for hours. Two Alberta Health Services employees were later fired.
British Columbia's provincial health officer also said last month that Vancouver Canucks players also jumped the line when they received vaccinations.