Juan Mata
Juan Mata has been limited to a bit-part role during Manchester United's pre-season tour of the United States PAUL ELLIS/AFP/Getty Images

Manchester United have received a potential fitness boost before their final United States tour clash against Barcelona, with Juan Mata returning to the training pitch ahead of that eagerly-anticipated match at FedEx Field in Maryland.

The Spanish playmaker missed the International Champions Cup wins over Manchester City and Real Madrid due to an ankle injury suffered just 15 minutes after he was introduced as a half-time substitute during a 2-1 defeat of Major League Soccer (MLS) outfit Real Salt Lake in Utah on 18 July.

However, Jose Mourinho expressed hope that the issue was not too serious and predicted that Mata would only be sidelined for a matter of days or a week at most.

United have now released a video via their official website showing Mata, working alone with a member of medical staff, jogging through cones while the rest of the squad train under Mourinho.

It is not yet clear if the 29-year-old will be fit enough to play any part in Wednesday's (26 July) meeting with Barcelona, with United scheduled to train again later today at their Washington DC base before the manager addresses the media.

If he is not quite ready for that high-profile fixture, then Mata could make his return on Sunday when the Red Devils fly to Oslo to face Norwegian side Valerenga IF. Mourinho's Europa League winners round off pre-season against Sampdoria at Dublin's Aviva Stadium on 2 August and then travel to Skopje for the Uefa Super Cup before kicking off the 2017-18 Premier League season at home to West Ham United.

United will already be without long-term absentees Marcos Rojo (knee), Luke Shaw (foot) and Ashley Young (groin) for the foreseeable future after Mourinho reiterated that there was "no chance" of any of that trio being fit for the start of the new campaign.

Menawhile, Ander Herrera's status for Barcelona remains uncertain after he lasted only six minutes against Real Madrid in Santa Clara before limping off with an apparent rib injury sustained during a collision with Oscar Rodriguez.

"It must at least be very painful because for Ander to come off, it has to be very painful," Mourinho said afterwards. "I want to wait and see what it is. I always say to the players that you don't risk anything in friendly matches. If you feel something is coming, even if it is a little injury, get off because the result is not important.

"It was very painful, it was in front of the bench, it was a bad contact. Maybe it is his ribs but I don't know."

Centre-back Eric Bailly will be available to face Barcelona, although has been ruled out of both the Super Cup meeting with Real Madrid in Macedonia and United's Champions League group stage opener after being handed an additional two-match ban by Uefa.