The England international forward missed last weekend’s match against Arsenal at Old Trafford due to a leg injury.
The 29-year-old was taken off at half time during the match against Crystal Palace at Selhurst Park after sustaining a painful dead leg.
Rooney has now recovered from that problem and will start against relegation-threatened Hull at the KC Stadium.
“Rooney is available,” Van Gaal told MUTV. “He is captain, so he shall play.”
Goalkeeper David de Gea, though, is doubtful for the match. The Spain international picked up a hamstring injury towards the end of the encounter against Arsenal.
“That I don’t know yet,” said Van Gaal when asked if the former Atletico Madrid star would be fit to face Hull.
“He has trained today but only with our goalkeeper trainer. He still has a little problem so I want to wait a day longer because I want him to play against Hull City."
United will head into Sunday’s round of matches in the Premier League placed fourth in the table with 69 points from 37 matches.
The Red Devils are two points behind Arsenal, who are third and are effectively guaranteed to end the season in that position due to their superior goal difference.