"As you get older, the opportunities are less and less no matter if you're a franchise quarterback or not," McCown said after the Bucs dropped to 1-8 Sunday following a 27-17 loss to the Atlanta Falcons.
"When you're 35 years old you know that the clock is ticking. You don't want to let these moments slip away," he said. "I think that's why it hurts because it got away."
Matt Ryan threw for 219 yards and one touchdown, helping the Falcons stop a five-game losing streak. Atlanta (3-6) won for the first time since embarrassing their NFC South rivals 56-14 on Sept. 18, a game in which the Bucs lost McCown to a thumb injury.
McCown returned to Tampa Bay's starting lineup for first time since loss, throwing for 301 yards and two TDs. His 1-yard scoring pass to Austin Seferian-Jenkins put the Bucs ahead 17-16 early in the fourth quarter. But Ryan drove the Falcons right down the field, throwing a 5-yard touchdown pass to Roddy White and a two-point conversion to Harry Douglas.
"You have two choices," said McCown, occasionally pausing while speaking with reporters. "You can curl up in a ball and hide and hope that it goes away and it's over or you can do something about it. With our actions, not our words. With the way that we work, that will be the measure of us."
Steven Jackson scored on a 1-yard run and Matt Bryant kicked four field goals for the Falcons, one of them after a wide-open Devin Hester dropped what would have been a touchdown in the second quarter.
Ryan finished 20 of 31 with no interceptions. Jackson rushed for 81 yards on 16 carries, Julio Jones had eight receptions for 119 yards and White had six catches for 72 yards.
McCown completed 27 of 43 passes, threw a pair of interceptions in the final two minutes and was sacked four times. Rookie Mike Evans had a big game for the second straight week with seven receptions for 125 yards, including a 22-yard TD catch that gives him five in his past five games.
"We realize what our record is ... it's a broken record really," Tampa Bay coach Lovie Smith said. "Losses, of course, piling up. Too many. There's a lot of good things we did, but critical situations we didn't come through."
Dwight Lowery's end-zone interception stopped a Tampa Bay drive that reached the Atlanta 4 with 1:49 remaining. Josh Wilson picked McCown's final pass of the day.
Despite how poorly the Falcons and Bucs have played for much of the season, each entered Sunday clinging to hopes of working their way back into the NFC South race, where no team has been able to take control.
The Bucs went 1-4 with Mike Glennon at quarterback in McCown's absence, but an anemic offense wasn't the only reason for their struggles.
A leaky defense, which was expected to be the team's strength in their first season under Smith, has had problems getting off the field on third down and also has a knack for allowing opponents to put together long scoring drives at critical points of games.
It happened again Sunday in both halves.
McCown's TD pass to Evans made it 10-10 with 46 seconds remaining in the second quarter. But Ryan encountered little resistance in moving the Falcons downfield to kick a 43-yard field goal for a three-point lead at the half. The Atlanta quarterback led a 10-play, 65-yard drive after McCown's TD pass to Seferian-Jenkins put Tampa Bay ahead less than a minute into the fourth quarter.
Evans was the seventh pick in the draft after being Johnny Manziel's favorite target at Texas A&M. He's caught at least four passes in each of the eight games he's played. Vincent Jackson had eight receptions for 75 yards for Tampa Bay.