Ronaldo has been heavily linked with a move away from Old Trafford this summer although United are adamant he is not for sale.
- Notebook: United told Ten Hag to lower expectations
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But speaking at a news conference on Friday, Ten Hag said it was an "assumption" the 37-year-old wants a move and hinted that privately he has said he wants to stay.
"That is your assumption [that Ronaldo wants to leave] -- that is not what he is telling me," said Ten Hag.
"I deal with the players we have and we plan with him for this season and we are happy with him and we have to fit him into the team so he has to come at the right fitness levels so that he can do the job that we expect him to do.
"In every press conference we already confirmed that he is in our plans. We plan with him so we also plan around him."
Ronaldo has been reintergrated back into the squad after missing the tour of Thailand and Australia to deal with a family issue.
He could start against Brentford on Saturday with Anthony Martial still sidelined because of a hamstring problem and Ten Hag says the injury to the Frenchman has highlighted the need for a more options in attack as well as in midfield.
United have an agreement in place with Juventus over the transfer of midfielder Adrien Rabiot, sources have told ESPN. Discussions are said to be progressing well between Rabiot's mother, who represents the player, and United's football director John Murtough, with talks set to continue.
Ten Hag said the reasons behind United's sluggish summer recruitment are "complicated" but says he's happy with how the club are going about their transfer business with just three weeks to go before the deadline.
"We co-operate well and it is to my satisfaction," he added.
"It was better to get the players earlier in because then you get earlier in the process and now we are in the department of midfield and offence you have seen when we have one injury then we have a problem. That's clear.
"It's really complicated but I think we are really happy with what we have done until now. They [new signings] have to be good and fit into the team.
"I would say panic isn't the right word. It's more like, 'come on, we have to act.' "We have to think bright and do the right things."
Information from ESPN correspondent Julien Laurens was used in this report.