PITTSBURGH (AP) -The Pittsburgh Steelers aren't saying if quarterback Ben Roethlisberger sustained his second concussion in slightly more than four months.

Roethlisberger was fit enough to fly home with the Steelers following their 41-38 overtime loss Sunday in Atlanta, and to drive his SUV to a team meeting Monday, despite being briefly knocked unconscious during a helmet-to-helmet hit with the Falcons' Chauncey Davis.

By definition, a concussion is a disruption of the brain's activities caused by a sudden blow to the head - much like the hit Roethlisberger absorbed while being sacked by multiple defenders. Doctors who have studied concussion patients have said some act and look fine within hours or even minutes of being injured, while others take longer to look normal.

The Steelers' biggest concern is if this is Roethlisberger's second concussion in slightly more than four months. He sustained a severe concussion, and needed seven hours of surgery mostly to repair facial injuries, when his motorcycle collided with a car June 12 in Pittsburgh.

A football player receiving a second concussion in a relatively brief time can be susceptible to succeeding concussions, according to various concussion-related studies by doctors who have studied the issue for the NFL. Also, a player receiving multiple concussions in a brief time span may need a longer recovery time before playing again than one coming off his initial concussion.

This time, Roethlisberger lay on the turf for about five minutes, then was unsteady while being led off the field. He also looked dazed while riding to the locker room on a motorized cart. But he was back on the sideline later in the game and looked normal afterward.

``I was just hoping and praying they didn't have to bring out the stretcher,'' said backup Charlie Batch, who had flashbacks to Chiefs quarterback Trent Green's head injury earlier this season when he saw Roethlisberger go down. ``You never want to see anybody hit like that.''

The Steelers did not provide an update Monday on Roethlisberger. Unlike most NFL coaches, Bill Cowher doesn't hold a news conference on Mondays or allow anyone else in the organization to speak about injuries. He will talk to reporters on Tuesday.

The Steelers have been among the NFL teams most proactive in concussion-related studies, research and testing. Several doctors who undertake such work for the NFL and NHL are associated with the Steelers or have offices in the complex where the Steelers' practice facility is located.

Roethlisberger was not wearing a helmet during the motorcycle crash and also decided against wearing the recently designed football helmet that affords more protection against head injuries.

Cowher may say Tuesday if Roethlisberger has any chance to play Sunday for the Steelers (2-4), losers of four of five, against the Oakland Raiders (1-5). The Steelers are 0-3 on the road. If not Batch would replace him, as he did Sunday and in the Sept. 7 season opener against Miami when Roethlisberger was out with appendicitis.

Batch might be the NFL's most dependable backup, going 3-0 as a starter the last two seasons. He is 24-of-39 for 410 yards, five touchdowns and no interceptions this season and threw for two touchdowns and 195 yards after replacing Roethlisberger on Sunday.

``I started to get in a groove and I got more comfortable out there,'' Batch said.

Roethlisberger's injury came during his second strong performance in as many weeks. After throwing seven interceptions and no touchdown passes in his first three post-crash starts, all losses, he was 32-of-41 for 476 yards, five TDs and no interceptions against the Chiefs and Falcons.

A week after seemingly righting their season by beating Kansas City 45-7, the Super Bowl champion Steelers again trail Baltimore (4-2) and Cincinnati (4-2) by two games in the AFC North.

``I still think we're a great football team,'' defensive end Brett Keisel said. ``I still think we have the players in here to do exactly what we did last year. But it's going to be tough with (Sunday's) loss.''

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