However, interim manager Ole Gunnar Solskjaer is convinced Jones is a United-standard player.
Sanchez has struggled to convince since arriving from Premier League rivals Arsenal in January previous year, while former boss Jose Mourinho repeatedly called on United's hierarchy to spend more in the quest for success.
Martial, 23, has scored twice and United are unbeaten in ten games since Solskjaer took over in December.
Despite costing vast amounts of money in transfers and salaries, Di Maria and Falcao (loan) left Old Trafford after one season.
Jones' injury record and inconsistent form has hampered his development at Old Trafford and doubts remain over whether he is good enough to cut the mustard regularly at the heart of the United defence.
"I am delighted to have signed a new contract", he said.
The Portuguese coach questioned United's ambition after an outlay of close to £70m brought in Fred, Diogo Dalot and Lee Grant over the summer, but Solskjaer thinks the foundations of a title-winning squad are already in place.
"It's a signal for the players we believe in them, for the supporters that we plan ahead", Solskjaer said.
The 26-year-old was due to become a free agent at the end of the season but is now tied to United until at least June 2023, with the club reserving the option for an additional 12-month extension.
"I am excited about the challenges that lie ahead of us as we prepare for a very busy period in the season".
"The focus has been around the PSG game for a long time, Chelsea and Liverpool, but they're not the games that will move us up the table".
Manchester United have the opportunity to hoist themselves into the Premier League's top four if the Reds beat Fulham.
"I think it is about who we've got here", Solskjaer told a news conference on Friday.
"They know the league and the club inside out, so to pass that on and get us playing how we are has been flawless".