United have lacked defensive stability so far this season and the situation looks unlikely to change with so many players currently unavailable for selection.
Speaking at his pre match press conference, Van Gaal said: “We have nine injuries and one suspension with Blackett. The younger players can have their chance now.
“Evans’ bone is bruised. Smalling left yesterday’s session because he had stiff legs. I won’t take risks with players.”
They are part of a long injury list that also includes Ashley Young, Marouane Fellaini and Jesse Lingard as United’s injury woes continue this season.