Saturdays match against Atletico Madrid is expected to be a dress rehearsal for the Premier League opener against Brighton, while Sundays clash versus Rayo Vallecano will be one for those on the periphery to stake a claim for a starting spot.
Both matches should give us a clear idea of the United pecking order heading into the new campaign, with the two line-ups acting as a clear indication of who is currently viewed to be at the top of their hierarchy, and who still has work to do.
Ten Hags selection is complicated by matters surrounding players with uncertain futures at the club. There are a group of players who are free to leave before deadline day who represent a dilemma of whether to leave them out or utilise them to keep them fit and place them in the proverbial shop window.
Uncertainty over Cristiano Ronaldos future remains the main talking point following his talks with Ten Hag this week. The 37-year-old wants to leave to pursue another season playing in the Champions League but United are adamant he is not for sale and are under no financial obligation to get rid of him.
Thats the case in defence, where United are happy to let Aaron Wan-Bissaka and Alex Telles leave this summer but have had to use both players in pre-season.
Wan-Bissaka is now back-up to Diogo Dalot with Ethan Laird as the understudy, and United remain in the market for another right-back before deadline day.
Telles is the third choice behind Luke Shaw and Tyrell Malacia and has been used as a utility player this summer. His opportunities will diminish now that a deal for Lisandro Martinez has been completed.
That transfer will also have knock-on effects for centre-back trio Eric Bailly, Phil Jones and Axel Tuanzebe who are all surplus to requirements and can leave if appropriate offers come in.
Then there are fringe players who could do a job in the first team next season but who might be better off heading out on loan again to get more meaningful match time.
James Garner excelled at Nottingham Forest last season but remains down the pecking order at Old Trafford and might be better suited to a Premier League spell this summer.
Amad and Facundo Pellistri have the raw talent to address Uniteds right wing issue in the future, but are currently below the standard required and might also benefit from loan deals. The same can be said for Tahith Chong, who is entering the final year of his contract and should be sold if a fee can be attained.
Charlie Savage and Zidane Iqbal both shone when given a chance on the pre-season tour but may struggle for playing time this season and might be better off heading out on a temporary deal.
Much of the focus is on who United might add to their squad by deadline day, but just as important is who they manage to shift the other way.
Ronaldo might have been surprised by teammates at Carrington