The Blues chief was left frustrated on Boxing Day as frozen pipes at Goodison Park resulted in the postponement of the Premier League clash at Everton. It means that the side could face some fixture congestion as the pre-Christmas clash with Newcastle also bit the dust due to heavy snow at St Andrew's.
However the extra couple of days off will have given Hleb more time to recover from his hamstring problems and he could be in the squad to face the Red Devils, while Keith Fahey, David Murphy and Liam Ridgewell have all had more time to shake off recent illness issues.
McLeish, who watched United defeat Sunderland 2-0 at Old Trafford after the Blues' game on Merseyside was called off, said: "When you're playing a couple of days later, everybody does tend to feel it, the lactic acid is still in the body. But it is what it is this time of year.
"And we're not going to be looking at these postponements negatively; we await the United game in anticipation. Everyone is very eager to get out there."