The Eagles added injury to insult on Monday when they learned that starting cornerback Ronald Darby tore the anterior cruciate ligament in his right knee in Sunday's 27-20 loss to the Dallas Cowboys, ending his season and putting his future with the Eagles in question.

"It's unfortunate," coach Doug Pederson said.

That's an understatement. In a depleted secondary, the Eagles had been counting on Darby as a top cornerback. He has started all nine games this season, with 12 pass breakups and one interception.

It's also devastating for the 24-year-old Darby, who is in the final year of his contract and was set to become an attractive free agent this offseason. Considering the injury occurred in November, Darby likely won't be able to return until next summer or fall.

Darby's future, with the Eagles or elsewhere, will have more clarity in the offseason. The Eagles must determine how to replace him for the remainder of the season. Undrafted rookie Chandon Sullivan filled in for Darby on Sunday, but that was because the Eagles played without Jalen Mills and Sidney Jones.

Jones, who has missed three games with a hamstring injury, is close to returning. Mills, who missed Sunday's game with a foot injury, will take longer to return.

Jones has been a slot cornerback this season, but he can move to the outside to replace Darby. The Eagles also have Rasul Douglas, who started in Mills' place against Dallas.   Jones and Douglas could be the starters on Sunday when the Eagles play the 8-1 New Orleans Saints, led by MVP favorite Drew Brees. It all depends on whether Jones recovers.

"Right now, obviously, we'll see Sidney and where he's at this week," Pederson said. "We have a couple days to have some discussion, and then see where our players are after practice on Wednesday. But you'll probably know more probably Wednesday on the plan on that."

Avonte Maddox  tackling the Cowboys’ Cole Beasley,  played slot cornerback on Sunday.
DAVID MAIALETTI / Staff Photographer
Avonte Maddox  tackling the Cowboys’ Cole Beasley,  played slot cornerback on Sunday.

The Eagles don't have much experience behind them, and they would need to figure out whom to play in the nickel defense, too. Sullivan and Cre'Von LeBlanc are the other two cornerbacks on the roster. LeBlanc was claimed off waivers from Detroit last week, but he did not take any defensive snaps against the Cowboys. Avonte Maddox was drafted as a cornerback and has since moved to safety. However, he played as the slot cornerback against the Cowboys.

The Eagles could also promote DeVante Bausby from the practice squad. Bausby had a good spring with the team, but he did not make the 53-man roster. Pederson called Bausby another possibility.

It's a bad situation for an Eagles defense that couldn't stop Dallas in the second half without Darby, and has looked leaky at times this season even with Darby on the field. Defensive coordinator Jim Schwartz will address reporters Tuesday.

Darby will become the ninth Eagle to go on injured reserve. The group includes starters Rodney McLeod, Jay Ajayi, Derek Barnett, and Mike Wallace.

Injuries are a reality of the NFL; the Eagles won the Super Bowl last season despite a series of high-profile injuries. What's different this season is how the injuries have been concentrated in certain positions. Darby will become the fifth of the Eagles' top six defensive backs to miss time this season. Pederson jokingly asked if a reporter had any eligibility remaining. It wouldn't have been the first time the Eagles plucked someone off the street to play in their secondary.

"It is hard," Pederson said. "It's hard because you're asking players that maybe don't get a lot of practice time during the week to come and play. They're on the [scout]  teams. Maybe they're giving a look to the offense or whatever it is. Next thing you know, they're having to play. We've just got to continue to coach those guys up just like we do everybody, and make sure now moving forward that they're ready."

No matter which player steps in, the Eagles will miss Darby. They paid a steep price to acquire him in August 2017 when they dealt Jordan Matthews and a third-round pick to Buffalo. Darby immediately became a starter, and after recovering from a dislocated ankle that kept him out the first half of last season, he returned to start for the Eagles during the stretch run and in the playoffs and Super Bowl.

They won as underdogs praised for their resilience in overcoming injuries. They haven't had that same success this season, and Darby's injury only adds another obstacle in a season in danger of being lost.