Manchester United head coach has expressed injury concerns over defender Phil Jones and winger Ashley Young following the club's 2-1 win over Swansea at Old Trafford.
Jones was on Saturday replaced with Matteo Darmian at half-time while Paddy McNair came on for Young in the second half.
Van Gaal revealed that Jones picked up an injury similar to the ankle problem that forced him to miss five games before Christmas while Young's withdrawal was a consequence of the busy fixture list over the festive period.
"Phil Jones is injured, and it's more or less the same injury as before," van Gaal said. "Ashley Young has played a lot of matches in a row, so he was stiff and had to be changed. It was not voluntary, I changed them because I need to change."
The Dutch tactician also clarified the reason behind midfielder Ander Herrera's late substitution, after the Spaniard came off with just minutes remaining in the game. He added: "With Herrera, it was because I wanted to waste time, as Swansea did all match."
United are still without Jesse Lingard (hamstring) and three players who have had surgery this season -- Marcos Rojo (shoulder), Antonio Valencia (ankle) and Luke Shaw (broken leg).