They pretty much have no choice.
With Leonard Fournette out indefinitely with a right hamstring strain and Corey Grant potentially out for the season after suffering a Lisfranc injury in Sunday's 30-14 loss at Kansas City, Yeldon is going to be the focal point of the run game for the foreseeable future. It's a role he handled pretty well as a rookie, and he says he'll have no trouble assuming it again.
"I've been doing this all my life," Yeldon said after rushing for 53 yards and catching eight passes for 69 yards and a touchdown at Arrowhead Stadium. "Whatever the team needs me to do, I'm going to do. No pressure at all. I'm locked in. I'm ready."
Brandon Wilds is the only other healthy running back on the roster. He spent the first week of the season on the practice squad, was promoted after Fournette hurt his hamstring in the season opener and has six carries for 15 yards in the past three games. He had not had a carry in a game since 2016 and now has 16 carries for 42 yards in his career.
The Jaguars will have to sign at least one other back this week. The team worked out Orleans Darkwa and Matthew Dayes last Tuesday and expect to have more backs in for workouts early this week.
Even so, Yeldon will be featured, as he was in Weeks 2, 3 and 4. He's averaging 4.4 yards per carry, and he has 258 yards and one touchdown rushing and 22 catches for 194 yards and three touchdowns receiving.
He's averaging 86 yards per game in games in which Fournette does not play, which is better than what he averaged as the Jaguars' feature back as a rookie in 2015. Yeldon ran for 740 yards in 12 games (61.7 yards per game).
"T.J.'s been playing lights-out," safety Tashaun Gipson said.
Yeldon is in the last year of his rookie contract with the Jaguars, so this is a good chance for him to prove that he is capable of having a bigger role than he does when Fournette is on the field, which is as a third-down back. That could mean a bigger contract after the season -- in Jacksonville or somewhere else.
"I just play football," Yeldon said. "That contract stuff is going to work itself out, and I'm going to be ready whenever. I'm always going to be ready. I'm always locked in. ... I'm going to continue to be the best player I can for my team."
It isn't going to be easy, though. The Jaguars lost starting left tackle Cam Robinson to a knee injury in Week 2, and replacement Josh Wells went down with a groin injury in the loss to the Chiefs. That put Josh Walker, who first played left tackle in the preseason finale, into the lineup.
Those injuries along the offensive line -- center Brandon Linder gets every Wednesday off to rest his knee -- will impact the ground game as well and could make life tougher for quarterback Blake Bortles to consistently put drives together. Bortles was sacked five times against the Chiefs and Walker, and right tackle Jermey Parnell really struggled.
Coach Doug Marrone said the team will have to figure out a way to get things done. It's not like there's a 1,000-yard rusher or starting-caliber left tackle out on the street waiting to be signed. Plus, there's no timetable for Fournette to return. He missed two games with the original injury, and Marrone said last week that the latest injury is no worse than that, so expect Fournette to miss at least one more week. It's possible the team could opt to rest him until after the bye week and have him return Nov. 11.
"We have been banged up quite a bit this year," Marrone said. "It is one of those things that is part of the NFL. You just have to get the guys ready. We have to coach them to be ready to play, and they have to go in there and step up because no one really feels sorry for you here. We are not going to use that as an excuse."
The Jaguars were 4-0 in games in which Fournette did not play, and that prompted some to wonder if the Jaguars were better on offense without him because it made them more aggressive on first downs and made Bortles the centerpiece, which is the way pretty much every other NFL team operates.
However, the past two games without Fournette have been losses to Tennessee and Kansas City. The Jaguars are minus-4 in turnover ratio in those games and have scored just two offensive touchdowns. The Jaguars had just two field goals against the Titans and didn't score against the Chiefs until 3:10 remained in the third quarter.
"We have to find a way to get going early," Bortles said. "We have to find a way to make plays early, sustain drives and get it rolling. It felt like we waited until we were down and in a bad place until we decided we wanted to play, and that can't happen. We have to start from the beginning at the first snap playing as hard as we can play to do everything we can to be successful and score points."
Yeldon has to be a major part of that.