JACKSONVILLE, Fla. -- He hasn't caught a pass or even run a route this year, but one of the Jacksonville Jaguars' MVPs can be found in the receivers' meeting room.

No assistant coach's job this season can be tougher than what Keenan McCardell has faced. He has lost his top three receivers -- one for the entire season -- at different points this season and has had to lean heavily on a fourth-round draft pick and two undrafted players.

They've thrived and it's because of McCardell, who is in his first season as the Jaguars' receivers coach.

"I can't say enough," head coach Doug Marrone said. "Out of all the positions that we've had he's been the most challenged from the young players, and the players obviously have responded to him.

"That's the other thing that you look for, how the players respond, and he's done a great job in teaching those players and the work ethic and the way they work and technically how much they've gotten better, so he's done an outstanding job."

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McCardell hasn't been a coach long, beginning his career as the receivers coach for the Washington Redskins in 2010-11 before spending the 2014-16 seasons as the receivers coach at Maryland. He joined the Jaguars' staff in January and has turned out to be the most important hire that Marrone and executive VP of football operations Tom Coughlin made.

Here's what McCardell has had to deal with since August:

Fourth-round pick Dede Westbrook, who led all NFL receivers in the preseason with 288 yards and was going to figure prominently in the rotation, developed a sports hernia that needed surgery. He had the surgery on Sept. 12 and was placed on injured reserve.

Allen Robinson, the Jaguars' No. 1 receiver, suffered a torn left ACL in the season opener against Houston on Sept. 10 and was lost for the season.

Before the first half of the season opener the Jaguars were down two receivers. That meant undrafted rookie Keelan Cole had to shift into the No. 3 spot. It was a rough adjustment and he clearly was overwhelmed the first two months of the season.

Marqise Lee and Allen Hurns had to carry the group, which was working out OK until Hurns suffered a severely sprained right ankle in the Jaguars' victory over the Los Angeles Chargers on Nov. 12. He hasn't practiced or played since.

McCardell was forced to rely on Lee, Cole and Westbrook, who made his season debut the week after Hurns' injury. Then Lee went down with a sprained right ankle in the first quarter of last Sunday's victory over Houston and McCardell had to turn to first-year player Jaydon Mickens, the Jaguars' punt returner who had just one career catch.

Cole, Westbrook and Mickens -- who entered last Sunday's game with 46 career catches -- combined to catch 13 passes for 268 yards and three touchdowns against the Texans.

Their ability to not only step into major roles but to also produce at a high level is a direct result of the work McCardell has done with the group, Marrone said. The fluctuation in the lineup, as well as bringing the young, inexperienced players along quicker than originally anticipated, is a tough ask for any coach, but McCardell has flourished in the role.

That McCardell had an accomplished NFL career certainly helps with the young receivers. Not only is he second in Jaguars history in receptions (499) and receiving yards (6,393), he finished his 16-year career with 883 catches and 11,373 yards and 63 touchdowns. He also won a Super Bowl with Tampa Bay in 2002.

"The one thing about coaching is that we all rely on each other to make sure that we all do a good job because if one of us doesn't do a good job at our position group, then obviously then that can cost us a game," Marrone said. "I think Keenan's been challenged greatly. ... You get some young guys around and you're like, 'OK, hey, we've got some time to bring these guys along and they can learn from the older guys,' and then all of a sudden A-Rob's not around, and Hurns is going through some things, and Marqise is going through some things and Dede got injured, so we had to keep him up to speed because we knew when he came back he had to be ready.

"I really think he [McCardell] has done an outstanding job."