Walls is a 6-4, 230-pound linebacker/defensive end prospect from Olive Branch, Miss. He got a three-star rating from Scout.com after recording 92 tackles and 13 sacks last fall.
Hughes is a 6-5, 275-pound defensive tackle prospect from Murfreesboro. He earned a three-star rating from Scout.com after registering 106 tackles and 13 sacks as a prep senior last fall.
Meanwhile, four players have health issues that are keeping them from practicing at full speed.
Redshirt freshman offensive tackle William Brimfield continues to recover from ankle surgery.
"We're expecting him to be out there and working some but he's probably at least two weeks – maybe three weeks – from being full speed," Fulmer said.
Jeff Cottam, a 6-8, 260-pound junior tight end, continues to be sidelined by a fractured fibula.
"Jeff hasn't responded as well as we'd like," Fulmer said. "That is definitely a concern for us. We expect him in two or three weeks to be back at full speed ... certainly before we get to Game Week."
Aaron Douglas, heralded freshman tight end, continues to recover from shoulder surgery he underwent as a senior at Maryville High School. Fulmer is encouraged, however, because Douglas appears to be "well ahead" of schedule.
"We're hopeful to get him in the mix as fast as we can," the coach added. "Obviously, early we need to be a little bit cautious. He doesn't need to fall on that thing or something that might set him back."
Josh Hawkins, a tailback-turned-linebacker who redshirted as a freshman last fall, continues to be hobbled by a foot injury.
"Josh is still a little bit limited with his foot," Fulmer said, "but we've challenged him from a toughness standpoint; there's a difference between pain and injury. We'll get him out there and see how quickly he can go at the new position."
"I think David naturally is frustrated," Fulmer said. "This is the second year he hasn't been able to play. We're certainly sorry for that but it isn't anybody's fault. It's part of football. It happens.
"David wants to continue to play but there's a decision to be made that's beyond me or him. It's a medical decision as to what's best for him when he's 40. So we'll have to wait and see."
On a positive note, the head man said several players appear fully healed following offseason injuries.
"Chris Walker looks to be 100 percent from his surgery from an offseason injury prior to spring practice," Fulmer said.
Junior tailback Montario Hardesty, whose career has been plagued by a rash of injuries, appears healthier than he's been in a long time.
"Thank goodness," Fulmer noted, "Montario Hardesty looks to be well and ready to go and in great shape."
Senior wideout Lucas Taylor, who led the Vols in receptions (73) and receiving yards (1,000) last fall, appears fully recovered from shoulder problems that sidelined him all spring.
"Lucas Taylor has done a great job with his shoulder," Fulmer said, "and he's 100 percent."
"I compliment our medical staff, our training staff and our rehab guys," Fulmer said. "They've done a really good job with those players."