The 30-year-old could be allowed to leave Paradise Park for £2 million, and a return to the English top-flight could also interest the former Aston Villa man.
Blades manager Chris Wilder reckons Sinclair’s experience in the Premier League and quality could help boost his side’s chances against the bigwigs next season, but it is unknown if both parties have entered into negotiations yet.
The winger scored nine goals in 33 Premiership games last term, weighing in with two more in nine appearances across other competitions.
The former Manchester City and Swansea man has played in 119 Premier League games having also featured for the likes of Chelsea, Wigan Athletic and West Bromwich Albion, and was instrumental to Celtic’s recent dominance in Scotland as they won the domestic treble thrice in a row.
Sinclair definitely can help improve Sheffield’s fortunes in the Premier League next term, but it remains to be seen if Hoops boss Neil Lennon will be keen to let him go.