Ched Evans and Regan Slater have both left Bramall Lane on a temporary basis.
Evans has joined Fleetwood Town on a season-long loan, whilst Slater will continue his development with Carlisle United.
Evans, who rejoined the Blades from Chesterfield last summer, made a total of 13 appearances in all competitions during 2017/18, in a campaign that was hampered by an ankle problem that required surgery.
Meanwhile, 18-year-old Slater, who made his United debut against Grimsby Town in November 2016, made two appearances last term.
Both have appeared for United in pre-season.