The Brighton man arrived to some fanfare in the summer after his displays for Blackburn last season but has failed to hit similar heights, starting only four times for the promotion-chasing Blades.
The winger has since joined Birmingham City on loan, saying: “When I got the call that Birmingham wanted me, I was excited to go somewhere and get some minutes and play more.”
We asked Blades fans on social media who they would like to see brought in as a realistic replacement, given budget limitations and squad profile at Bramall Lane. Here are some of the most popular options – including some familiar faces, lower-league gems and top-flight forwards ...
9. Ched Evans
Another former Blade touted for a return by Adam Weightman, @loukesj and Jonathon Chapman. In great goalscoring form for Preston who would value him higher than United can afford to pay this window Photo: Gareth Copley
10. Joe Gelhardt
Suggested by @FreddyTheFud, with Leeds reportedly willing to let him leave if they bring in new faces this month Photo: Ashley Allen
11. Keiffer Moore
No, not Gareth Bale now he's retired... Floated by Shane Robshaw, Moore is part of Bournemouth's squad plans and has played for them in recent weeks off the bench Photo: Christopher Lee
12. Keane Lewis-Potter
Suggested by @MrWardwide and Simon Hayden, Lewis-Potter cost Brentford around £16m in the summer but has missed some game-time with a foot injury. Made his return off the bench on Monday as Brentford beat Liverpool Photo: GLYN KIRK