The Red Devils are already beset by injury problems in defense, with several starters a doubt for the Community Shield against Manchester City on Saturday.
Ten Hag stated: "Harry Maguire missed the game (vs Liverpool), was a precaution but is still a question mark for Saturday. So we have training, we have to see whether he is fit enough or not to be available.
“Victor (Lindelöf) played but also he's a question mark and also Azza (Aaron Wan-Bissaka) and Luke Shaw are both question marks, we have to assess them tomorrow (Friday)."
He added on using his Copa America stars: "That is individual based, everyone has a different background, we put them on off-season programmes but they have different starts while we were in USA, we will assess them, make a decision whether they start, come from the bench or whether they don't play."
On Lisandro Martinez, he elaborated: "We think about Licha to be involved in the game."
And on the game itself, he finished: "So, we always want to win, also in all the friendlies. It's about trophy, we will put out a team that is very competitive to win this trophy. It's also pre-season, we don't go into big risks with players, the normal approach in to this game."