The Dutch forward has been out of action since the 2-1 defeat by Swansea City last month after picking up an ankle injury at the Liberty Stadium.
The 31-year-old striker is working with the Red Devils’ medical team as he continues his rehabilitation, but Van Gaal refused to put a time-scale on Van Persie’s potential return to action.
Speaking at his pre-match news conference on Friday, Van Gaal said: “He is still with the medical department and needs to take the step to the technical department.
“He is always training but the medical department is also sports science so he is training inside, not outside on the pitch. Even when he is on the pitch, he is with the medical department.
“He will then take the step to the technical department and then we have a process when he comes into our selection and trains.”
Van Gaal also revealed that defender Marcos Rojo is an injury doubt for Sunday’s clash with Spurs with a minor injury, but Luke Shaw should be available.
“Rojo is a little bit injured. You have to take care of the health of the players. He has a minor problem. Maybe I’ll take him out of the game against Tottenham Hotspur, but I have to decide,” he added.
Both Angel di Maria and Jonny Evans will miss the game against the north London side due to suspension.
Manchester United are currently fourth in the Premier League table heading into Sunday’s showdown.
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