Foster ran for 879 yards last fall but missed spring practice due to shoulder and knee problems. Coker was held out while recuperating from shoulder surgery. Hardesty was recovering from knee surgery.
Fulmer called the absence of the top three tailbacks last spring "a real minus," but said all three appear to be in tip-top shape heading into preseason drills.
"Arian Foster looks like he's 100 percent (healed) from the shoulder injury and the knee surgery that he had," the head man said. "That's a real plus for us because Arian's a guy who, with his hands on the football, can be dynamic.
"He's worked hard on his breakaway speed. He was already a physical back who's going to break tackles and fall forward. It's very difficult for the first guy to get him down but he's got a lot of work to do yet to be a complete back."
Fulmer said Coker "has learned how to work much better. He's a guy that also has changed his body, and I'm encouraged about him."
Hardesty carried just six times last fall before suffering a season-ending knee injury. He was supposed to sit out spring practice but sneaked into one drill long enough to make a couple of carries.
"Even though he's played a very limited amount, he's one of those guys who, when he has the ball in his hands, is fun to watch," Fulmer said.
"Between those three, I think we'll come out of it (preseason) with a really good running back. It's very important that we do that. In this league if you can't run the ball you're going to have a difficult time winning the championship."