The Jacksonville Jaguars will once again be without the services of running back Leonard Fournette for a while. Fournette aggravated his hamstring injury Sunday, and according to Jags coach Doug Marrone, the team does not know when he'll be able to return. 

"I really don't know," Marrone responded when asked when the team expects to have Fournette back on the field, per ESPN.com. "Believe me, if I knew exactly what the deal was and I could tell you -- three [games], six, 10, IR, whatever -- I would. I just don't know. Those injuries are tough. We talked about it by position. We talked about it by player. We've talked about it every other way. "I thought he was looking good. ... You guys see him working [in practice], but it's different when you're playing a game. The game's different."

The fact that Marrone is volunteering timelines of "three, six, 10, IR, whatever" is certainly not a good sign for Fournette's potential availability any time soon. Fournette previously missed the Jaguars' second and third games of the season with the hamstring injury, but was cleared to return to the lineup for Week 4. He ran 11 times for 30 yards and caught one pass for 5 yards before exiting the game with a similar injury as the one he sustained during the team's Week 1 victory over the Giants. 

"There's a thing that's just pulling at it," Marrone said of Fournette's hamstring. "It's legit. There is something there, and we've just got to do everything we can to get that out. That whatever thing is that feels like it catches. That's all I know. I don't know all the doctor talk about it. I'm just trying to give you the layman's talk. It's just, 'Hey, I just got this little thing. It feels like it catches. It doesn't enable me to open up.'"

The Jags went 1-1 in their two full games without Fournette as he waited for the hamstring to heal, beating the Patriots before losing an ugly game to the Titans. The team has also won each game that Fournette left early due to injury. The 2017 No. 4 overall pick missed two games due to an ankle injury (and one due to suspension) as a rookie, but still managed to run for over 1,000 yards during his debut season. In his absence, T.J. Yeldon will presumably operate as the lead back, while Corey Grant will play a role as a pass-catcher out of the backfield.