Sample is dealing with a broken right arm, while Marks is recovering from a torn ACL.
Jenkins has played in six NFL games, all with Oakland. He returned 10 kickoffs for a 22.1-yard average and returned six punts for a total of 49 yards.
Receivers coach Jerry Sullivan has declared that Lee will be brought along slowly after losing the entire OTA/minicamp period due to a knee injury.
"My understanding is that he'll be ready to go [next week]," Sullivan told the Florida Times-Union. "But we have to manage him a little bit to make sure he's OK."
Lee appears destined to skip occasional days of practice and have his reps limited when he does participate.
Sanders, who was a fourth-round draft pick in 2013, had a promising rookie season. He appeared in 15 games (four starts), totaling 51 catches for 484 yards and one touchdown. He was targeted 87 times.
Unfortunately, Sanders was pretty non-existent on offense in 2014. He appeared in 12 games (no starts), while catching just six passes for 55 yards.
Sanders also contributed on special teams as a punt and kick returner.