IRVING, Texas -- This was Jerry Jones' biggest football fear.
On the first day of training camp, Jones was asked about his biggest concern with this edition of the Dallas Cowboys. His answer came faster than Felix Jones hits a hole: the depth of the offensive line, or lack thereof.
Asked a similar question more than a month into the season, the ex-Arkansas Razorback offensive guard stuck with the same worry.
Suddenly, there's a spotlight on Jones' primary concern. The offensive line depth will be tested with right tackle Marc Colombo out at least six weeks while recovering from ankle surgery and a broken fibula.
"We have really been challenged when we don't have a good right tackle," Jones said in the locker room after Sunday's loss to the Green Bay Packers.
That hasn't been an issue since the beginning of the 2006 season, when Colombo earned the starting job. But it was a big problem the previous season, when rookie sixth-rounder Rob Petitti led the NFL in sacks allowed while starting every game.
And Petitti qualifies as a draft success by recent Valley Ranch standards when it comes to offensive linemen. Pro Bowl center Andre Gurode, a second-rounder in 2002, was the last offensive linemen drafted by the Cowboys who developed into a good player for the franchise.
A list of the offensive linemen the Cowboys picked since then: Tyson Walter, Al Johnson, Justin Bates, Jacob Rogers, Stephen Peterman, Petitti, Pat McQuistan, E.J. Whitley, James Marten, Doug Free and Robert Brewster. Among those players, only Johnson and Petitti started any games for the Cowboys, although Free is likely to join that club Sunday.
Head coach Wade Phillips didn't exactly exude confidence about Free, who filled in after Colombo was injured in the first quarter, following the review of the game film Monday morning.
"He did fine," Phillips said of Free. "He didn't hurt us."
Offensive line coach Hudson Houck confirmed Wednesday that Free would start Sunday. He was the most likely and logical choice.
McQuistan, who has been playing right tackle for the scout team, would likely have been released if rookie Brewster didn't suffer a torn pectoral during a summer weightlifting session. There's a reason the coaches made McQuistan inactive for the first nine games while making Free the backup for both tackles.
Other options could have been to move Pro Bowler Leonard Davis over a few feet and plug Montrae Holland or Cory Procter in at right guard. Davis played right tackle for the Arizona Cardinals in 2002, but he isn't comfortable at the position. And it didn't make sense to downgrade at two positions to fill one.
So that leaves Free to start against the Washington Redskins.
It's far too early to call Free, a fourth-round pick in 2007, a bust. Perennial All-Pro outside linebacker DeMarcus Ware, who practices against Free on a daily basis, said the young tackle is better than people think. Davis calls him "a gamer" who has the trust of his veteran linemates.
Free played well enough in his limited game action to provide some hope within the coaching staff and front office that he might develop into a starter. Now, he'll have to learn on the job.
The Cowboys didn't draft Free to play right tackle. That was supposed to be James Marten, picked a round ahead of Free and released after the first game of his second season. The 6-6, 313-pound Free is a natural left tackle with good agility and footwork. He doesn't come close to matching Colombo's strength or mean streak.
"Obviously it's hard to replace a guy like Marc just because he does so much," tight end Jason Witten said. "He's a mauler. He's a leader. He's one of those guys over the course of the game that really wears them down. But I thought Doug showed that he can play well. He's athletic, and I was impressed that in the middle of a game like that the setting wasn't too big for him."
Maybe Free is the guy who ends the trend of offensive line draft busts around these parts. If not, the Cowboys' offense is in trouble, just as Jerry feared.
Tim MacMahon covers the Cowboys for ESPNDallas.com. E-mail him at email@example.com.