Nov. 17 (Bloomberg) -- Philadelphia Eagles quarterback Donovan McNabb's misunderstanding of the National Football League's overtime rules is ``indefensible'' and may have hurt his team's playoff chances, former NFL running back Tiki Barber said.

McNabb said after the Eagles' 13-13 tie yesterday in Cincinnati that he didn't know the NFL's regular-season rule that if neither team scored during a 15-minute overtime period, the game would end in a tie.

``That's an indefensible comment that he made,'' Barber, now a commentator for NBC Sports, said in an interview that will air Nov. 22 on Bloomberg's ``On the Ball'' radio program. ``He will live to regret it for a long time.''

McNabb, a 10-year NFL veteran, said at a postgame news conference that he didn't realize games could end in ties until the final play of yesterday's extra period, when his coach called for a deep pass in a last-ditch attempt to earn the win.

``I never even knew that that was in the rulebook,'' he said. ``It's part of the rules, and we have to go with it. I was looking forward to the next opportunity to get out there and try to drive to win the game.''

The admission raises the question of whether McNabb had a sufficient sense of urgency as the clock wound down, Barber said.

``For Donovan to be in the situation and not press for it, that tie, even though it wasn't a loss, it kills them,'' Barber said. ``They're almost out of the playoff race right now.''

The tie, which was the NFL's first since 2002, left the Eagles at 5-4-1, in last place in the National Football Conference's East Division behind the New York Giants (9-1), and the Washington Redskins and Dallas Cowboys (both 6-4). Philadelphia is also 0-3 in division matchups.

Three Drives

The Eagles had three other overtime drives before taking possession at their own 37-yard line with seven seconds remaining when Bengals kicker Shayne Graham missed a 47-yard field-goal attempt that would have given Cincinnati the win.

McNabb was 28-for-58 for 339 yards, with 3 interceptions and a fumble in the game.

Barber, 33, had a decade-long playing career for the New York Giants in which he set a franchise record with 10,449 rushing yards. He was named to the Pro Bowl three times.

The analysts in the General Electric Co. network's studios said they thought McNabb was joking when he first said that he didn't know the rule, Barber added. If there was any doubt, McNabb compounded the blunder by not knowing that playoff overtimes are played until a winner is determined.

``I hate to see what happens in the Super Bowl and I hate to see what happens in the playoffs, to settle with a tie,'' McNabb said.

To contact the reporter on this story: Mason Levinson in New York at mlevinson@bloomberg.net. Scott Soshnick in New York at ssoshnick@bloomberg.net

Last Updated: November 17, 2008 16:50 EST