David Weir expects Wednesday evening's game at Raith Rovers to be the biggest test of United's pre-season tour to Scotland.
The Blades conclude the tour north of the border at Raith's Starks Park ground (7.30pm kick-off) after a 1-0 victory over Greenock Morton and a 1-1 draw with Cowdenbeath.
"I've played at Raith a bit, it is a nice, friendly place to go to," said Weir, from United's Scottish training base. "They have been in the Premier League, been in cup finals and whereas Cowdenbeath are part-time, Raith are full-time and have brought in some new faces recently.
"Myself, Cowdenbeath's manager, Colin Cameron, and Raith manager, Grant Murray, were all in the Hearts squad that won the cup in 1998 so I know the guys quite well and it will be nice to meet up with Grant."
Weir adds: "The aim, though, is to continue to build fitness. We may give a few lads 60 or 70 minutes at Raith, fortunately we have everyone available because everyone has taken part in training this week.
The Blades return south on Thursday and continue pre-season action at Bury on Saturday (3pm).