In June, Martial's agent publicly announced that the 22-year-old was pushing for a move away from Old Trafford and reports claim that he has rejected the offer of an improved contract from United. "It is important to work with Juan Mata, Alexis and Anthony Martial, who we think are the players we have for the start of the season".
Captain Valencia was then forced from the field three minutes later with an apparent calf injury and replaced by out-of-favour full-back Matteo Darmian.
Manchester United's preparations for the 2018-19 campaign continued on Sunday night with a draw against San Jose Earthquakes.
"A commanding central defender and another hardworking wide player are the areas manager Jose Mourinho will look to strengthen, with Tottenham's Toby Alderweireld and Chelsea's Willian among the names in the frame".
Asked if he still wants to make more signings before next month's deadline, he said: 'One thing is what I want and another thing is what is going to happen'.
"Matic has all the attributes to be Manchester United captain, but he arrived only one year ago", Mourinho told reporters at their training base in the US.
"But I never care much about the captaincy, I care more about the life in the dressing room and the leaders".
"There will be no (Romelu Lukaku) or (Marcus) Rashford, for sure, and we have to try with what we have".
Juan Mata's goal was enough to secure a draw in their first of five pre-season fixtures in the U.S., which moves to San Jose in Santa Clara, California, on Sunday.
The Portuguese coach has watched his side draw their opening two matches of the US Tour against Club America and San Jose before their first International Champions Cup match with Milan in LA on Wednesday.