A Minneapolis police car struck an exit ramp guardrail while escorting two Washington Redskins team buses to their game Sunday, prompting the two trailing buses to collide, authorities said.

Running back Silas Redd suffered back spasms while on the first bus that were serious enough to keep him out of the game, according to wire and several Washington, D.C., news media reports.

The crash occurred about 8:15 a.m. along eastbound Interstate 94 at the ramp to Huron Avenue, just short of the University of Minnesota's TCF Bank Stadium, according to the State Patrol.

One bus struck the other from behind, when the one in front abruptly braked because a police car out ahead crashed into a guardrail and came to a stop across the ramp, according to Patrol Lt. Eric Roeske.

The first bus also hit the guardrail as it avoided the squad car, according to Blaine-based Lorenz Bus Services, operators of the motorcoaches.

The officer was taken to Hennepin County Medical Center with minor injuries, Roeske said. There were also minor bus injuries among the bus passengers, he added.

In a statement Sunday afternoon, Lorenz said that "our drivers acted professionally, and the decisive action by the driver of the lead motorcoach likely prevented a more serious accident."

Redskins wide receiver Pierre Garcon tweeted a photo from inside one of the buses. It showed a shattered windshield. In the street ahead was a stretcher and the squad car turned sideways.

"So this just happened. But we are OK," he wrote.

The police escort leading the early wave of team buses missed the exit ramp, members of the team told the Washington Post. Coach Jay Gruden, who was riding in the seat behind a bus driver, described the incident to the Post as "pretty scary."

Team spokesman Tony Wyllie said the team was coming from its travel headquarters at the Westin Edina Galleria Hotel. He said these two buses were among five the team was using to head to the game. Otherwise, Wyllie said nothing about who might have been hurt or how many in the buses were injured.

The last of the coach buses were towed away more than three hours after the incident. The passengers on the two buses finished their trip to the stadium on other buses.

"As far as I know, this is the first [team] bus crash we've ever handled on a Sunday morning game day," Roeske said.

A Minneapolis police official said the department would have something to say about the crash and the officer later in the week.