Read on for the latest team news and a closer look ahead to the clash.
Date: Sunday, July 22
Time: 10 p.m. BST/5 p.m. ET/2 p.m. PT
TV: MUTV (UK)
Live Stream: MUTV (UK)
Despite uncertainty from manager Jose Mourinho over his exact arrival in the United States, Alexis Sanchez is set to feature after being granted a visa to enter the country and link up with his team-mates, per Goal's Sacha Pisani.
Per BBC Sport, David De Gea and Nemanja Matic—who were also at the World Cup—aren't expected to join their team-mates until next week, along with new signing Fred.
Per MLSSoccer.com, Earthquakes' Kevin Partida is out with a knee injury, while Quincy Amarikwa, Anibal Godoy and Fatai Alashe are doubtful.
United's pre-season preparations are still relatively young, but it's fair to say Mourinho has not been happy so far:
On Thursday, he saw his depleted squad held to a 1-1 draw with Club America 1-1, which saw Juan Mata cancel out Henry Martin's opener in punishingly hot conditions in Arizona.
He had cause to be happy with the performance of 18-year-old academy star Tahith Chong. The pacey winger impressed off the bench and played a key role in Mata's goal by supplying an excellent cross for Ander Herrera, whose subsequent effort rebounded to the playmaker.
As football analyst Dave O'Brien noted, he is an impressive young prospect:
United writer Dale O'Donnell is hoping the Red Devils will take care in his development:
With the likes of Lukaku and Rashford absent, he may well get another run-out and a chance to impress once again on Sunday.
More important for United will be to give minutes to Sanchez, whose visa issue prevented him from appearing against Club America and put him behind schedule in terms of being ready for the new season.
Having the Chilean at his best will be crucial to the Red Devils' success in the new campaign, so the quicker he's match fit and firing the better.
San Jose will resume their MLS duties with fixtures on the following Wednesday and Saturday, so they'll likely have an eye on them despite their illustrious opponents in Sunday's match.
The Earthquakes are bottom of not only the Western Conference but also the overall standings, having accrued just 12 points in 19 matches with just two wins to their name.
They have conceded 39 goals in that time, which will give hope to United's somewhat makeshift front line, but the result will not be of particular importance to Mourinho compared with the game time and performance of his first-team stars.