Sheffield United have made a mightily impressive start to the 2018/19 season...

Chris Wilder's men made a sluggish start initially, losing their first two opening games, but have bounced back well winning their last four league games.

The Blades will look to continue their impressive run of form with a tough away trip to Bristol City this Saturday afternoon; the Robins sit three places below Wilder's men in the Championship table in sixth position.

It's been a summer of transition at Bramall Lane, with ten senior players arriving at the Yorkshire club and sixteen senior players departing on either permanent or loan deals.

The opportunity is still there, however, for Wilder to strengthen his squad, what with the window still open for clubs to sign free agents.

With that being said, here we take a look at four free agents available to Sheffield United...

He may not have endured the greatest of times at Sunderland, but the former Bayern Munich defender was highly rated by both Sunderland and Bolton fans over the last two years, and could be a shrewd addition for the Blades.

Standing at 6-foot-5, the German can play either as towering centre-back or in defensive midfield, with his versatility a potential key asset for Wilder.

Blades fans stick their noses up at this suggestion, after Wallace's four-year stint at arch-rivals Sheffield Wednesday, but rivalry aside many Blades fans would agree that Wallace, when fully fit, is a tremendous player.

The 33-year-old, who departed Hillsborough at the end of last season, can provide the Blades with some real quality in depth on the flanks.

The Norwich City legend is still without a club following his departure from Carrow Road after his eleven year stint at the club, and despite being 36, Hoolahan could still do a job in the Championship.

James Collins would bolster United's defence, and is without a club following his departure from West Ham United last term.

The Welshman is subject to strong interest from Ipswich Town and Aston Villa at present, but Wilder should definitely look to make a move for the 35-year old.