Dallas Cowboys quarterback Tony Romo has a broken finger on his throwing hand.Dallas Cowboys quarterback Tony Romo has a broken finger on his throwing hand. (Ronald Martinez/Getty Images)

Dallas Cowboys quarterback Tony Romo could miss up to four weeks of NFL action after it was confirmed Monday that he has a broken finger on his throwing hand.

Romo broke his right pinky on the opening play of overtime in Dallas's 30-24 loss to the Arizona Cardinals on Sunday.

Cowboys head coach Wade Phillips said Romo won't need surgery, and the timing of his return "depends on how fast that heals." The Cowboys have three games before an open date Nov. 9.

Romo wasn't in the locker room Monday when it was open to reporters, but Johnson described Romo as being in good spirits.

With Romo out, 40-year-old backup Brad Johnson is expected to start for the Cowboys, who sport a 4-2 record this season. His last start was in 2006 for Minnesota but he'll get the call Sunday at St. Louis.

"Obviously, it's unfortunate for Tony to have to go through something like this. He'll recover quick; he has a great attitude about it," Johnson said. "At this time, it's really just important for the offense especially to just kind of catch on to my snap count and the way we manage the huddle … I'm excited about the opportunity, worked hard to get here."

Johnson, who came to Dallas last year, won a Super Bowl with Tampa Bay during the 2002 season and is the only Cowboys player with a championship ring.

After Sunday's slate of games, Romo ranks second in NFC passing with a 103.5 rating, having thrown for 14 touchdowns.

"Am I optimistic that we can win without Tony? Yes, truly I am," said linebacker Greg Ellis, in his 11th season with the Cowboys, longer than anyone else. "I'm just disappointed in this organization right now, from the whole deal of it. Things just aren't going really good.

In 2007, his first full season as a starter, Romo led the Cowboys to an NFC-best 13-3 record, but Dallas was upset by the Giants in the playoffs. He set team records with 335 completions for 4,211 yards and 36 touchdowns.

It was two years ago this month that Romo replaced Drew Bledsoe as the starter.

Johnson won a Super Bowl with the Tampa Bay Buccaneers in 2003, but he hasn't started a game since 2006, when he was a member of the Minnesota Vikings.

Romo has had Johnson as a backup since last season, when he threw only 11 passes.

The Cowboys scored 10 points in the final two minutes of regulation Sunday. They got the ball to open overtime, but Romo fumbled and had two incompletions. He started flexing his hand after recovering his fumble.

Then Arizona blocked the punt and recovered it for a game-ending touchdown, a play that also cost Dallas its punter, Mat McBriar.

McBriar was carted off the field, and an MRI on Monday showed he has a broken foot. He could be out two months, so the team will have to sign another punter.

The losses of Romo and McBriar added to an already trying time for the Cowboys, who before Arizona had a lacklustre victory over winless Cincinnati and were beaten at home by NFC East rival Washington.

With files from the Associated Press