De Gea's contract at Old Trafford expired at the end of last month with no agreement over a revised offer put to the former Spain international.

Onana, 27, kept eight clean sheets in 24 games in Serie A last season.

The Cameroonian also kept eight clean sheets in 13 matches in the Champions League last season - the most of any goalkeeper in the competition.

Ten Hag managed Onana at former club Ajax and the Dutchman believes the player is up to the level he demands and will easily adapt to life in the Premier League.

By contrast, Ten Hag is not convinced De Gea's ability with the ball at his feet is up to the required standard.

Although United's budget is limited by financial fair play restrictions, and there has still been no clarity over the club's ownership situation, Ten Hag feels a goalkeeper and a centre-forward are attainable, particularly as departures should cover some of the cost.

Onana would become United's second signing of the summer after midfielder Mason Mount joined the Red Devils from Chelsea for an initial £55m earlier this week.