Martial has been out of action with a minor muscular problem, while defender Darmian has been suffering with a shoulder injury.
The pair are expected to feature when Manchester United host Watford on Wednesday night at Old Trafford as they look to build on their 3-2 win over Arsenal last weekend.
Van Gaal also hinted that defender Chris Smalling could return for the Red Devils against the Hornets.
Speaking at his pre-match news conference on Tuesday, Van Gaal said: “Players are coming back in March, I think. We need players who are coming back because our programme is very full.
“Martial can play and also Darmian can play. Maybe Chris Smalling can play. We have to wait and see for tomorrow.”
Van Gaal also delivered the latest Manchester United injury update on some of the club’s long-term absentees.
He continued: “[Marouane] Fellaini and [Antonio] Valencia are the first ones to come back, I think.
“Except, of course, Martial and Smalling and Darmian – they are coming back, maybe already tomorrow. It depends how they feel tomorrow, but the chance is there that one of these three players already plays.
“Fellaini shall come into the last step of the process of team training, and also Valencia today has trained with the group, so they are coming back. Wayne Rooney is still in a brace.”
United head into Wednesday night’s game against the Hornets three points adrift of the top four heading into the final 11 games of the season.
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