Sancho, a £73million signing from Borussia Dortmund 18 months ago, has not featured for United since playing 52 minutes of a 1-1 draw at Chelsea in October and was left out of England's World Cup squad.
Ten Hag said last month Sancho was “not in the right status or fitness state” and he missed United's two-match tour of Spain, instead placed on an individual fitness programme in the Netherlands.
He has this week returned to the club's training ground at Carrington but his involvement has so far been limited to small group sessions as the 22-year-old concentrates on his own personal plan.
Sancho's continuing absence depletes United's attacking options but Ten Hag accepts there are processes in place which will ultimately benefit the club and player in the long run.
“I would like to have Jadon back as soon as possible, but I can't force this process,” Ten Hag said. “I will do everything that's in my power but some processes you can't force and this is one of them.
“I also have to show patience although I don't have patience because we have a lack of opportunities in the frontline, players who are available and capable to contribute not only in the Premier League but on the highest standard in football.
“Jadon is one who, when he is fit, he will contribute and we will have an extra option and so we have more chance to win a lot of games.”
Ten Hag, speaking ahead of United's FA Cup third-round tie against Everton, thinks Sancho is heading in the right direction, adding there is a long way to go before he can be considered ripe for a comeback.
“With the physical, there's also a connection of mental,” Ten Hag said. “I think he's now making good progress on the physical part and that will help him.
“I hope he can return quickly but I can't say how long it will be. In this moment, he is not fit enough, no.
“We have some hurdles to take. I think he's (heading) in a good direction. I can't force this process so I don't do. I would be really happy in the moment if he returned in the squad for team training, that's the next step.”
Sancho scored three times in his first eight appearances of this season, including the opener in a 2-1 win against Liverpool in August and the only goal of the game at Leicester the following month.
As for why someone of his calibre has had a marked dip, Ten Hag said: “Football players are not robots. No one is the same, I think for everyone you need an individual approach.
“Sometimes it's good to go away from the place where you're at daily and to get a new fight and spirit. People have a different approach and that can give you the right push to get back on track.”
Midfielder Donny van de Beek will miss the visit of Everton with a knee injury suffered against Bournemouth in midweek but Anthony Martial is available despite hobbling off in the same game.
Additional reporting by PA.