Manchester United's five most pressing concerns while World Cup stars take summer holiday

Jose Mourinho has again got his way with Manchester United's summer plans.

Just like last year, the Portuguese coach has based himself at UCLA in California to prepare for the new season. Money-spinning trips to the Far East and Australia will have to wait at least another 12 months.

It is not all good news, and Mourinho will have to do without the bulk of his senior squad in the United States and the five games against Club America, San Jose Earthquakes, AC Milan, Liverpool and Real Madrid.

United had 11 players at the World Cup this summer, with seven making it to the semifinals and all the way to the final weekend of the tournament. Paul Pogba, a newly crowned world champion, will need a holiday after his exertions in Russia, and Mourinho has already suggested the midfielder will not be ready for the opening game of the Premier League season against Leicester at Old Trafford on Aug. 10.

Even without a host of first-team players in America, Mourinho will have the chance to solve a number of issues before the start of the new campaign. Ahead of the first game against Club America in Phoenix on Thursday, ESPN FC has looked at the five most pressing concerns for the United manager.

1. Anthony Martial and Eric Bailly

Anthony Martial was left out of the France squad for the World Cup and Eric Bailly's Ivory Coast did not qualify, so both reported back to Carrington last week.

It has been an uncertain summer for Martial, whose agent, Philippe Lamboley, has been vocal about the 22-year-old's desire to leave Old Trafford. Bailly, meanwhile, hardly featured at all during the final months of the season and sources have told ESPN FC that he is keen to talk to Mourinho about his role going forward.

Both have contracts and United are under no pressure to sell. But Mourinho has been clear that he only wants players who want to be there and he will have work to do with Martial in particular.

Martial scored in three consecutive Premier League games in January, only to find himself forced onto the sideline after Alexis Sanchez's arrival from Arsenal. You can understand why he has doubts and why, perhaps, he feels he might be better off elsewhere.

2. What happens to last season's loan stars?

Andreas Pereira, Timothy Fosu-Mensah and Axel Tuanzebe have all returned to Old Trafford after spending time away last season. Mourinho and his coaching staff kept in touch with all three, but the tour of the United States will be a chance to see for himself if they have progressed while on loan. Mourinho doesn't usually like first-team squad members to play for the under-23s unless they are coming back from injury, so he will have to decide if there will be enough opportunities to warrant keeping them around. If not, another loan move is the best bet.

3. Is Sanchez back?

Sanchez had his moments for United last season -- his goal helped beat Tottenham in the FA Cup semifinal -- but he did not look the same player as the one who scored 60 Premier League goals in three-and-a-half seasons at Arsenal.

Mourinho insisted a summer off -- the Chilean's first since 2013 -- would help, and he will hope to be proved right. Sanchez back to his best would make United a different prospect next season.

Sources have told ESPN FC that the 29-year-old is expected in the United States after the club solved his visa issue. With so many big players on holiday, Sanchez will be key to how well United start the season.

4. Which youngsters can make the step up?

The World Cup has forced Mourinho to take a young squad to the United States and presented the likes of Ethan Hamilton, Mason Greenwood and Josh Bohui with a fantastic opportunity to impress.

Scott McTominay did so well last summer that he went on to play in key games against Liverpool, Chelsea and Sevilla. With seven youngsters on the trip this time, there is no reason why that could not happen again.

It will help that Kieran McKenna has made the step up to coach the first team after Rui Faria's departure. He has worked with many of United's promising youngsters at under-18 level and it will not have escaped Mourinho that a familiar face on the coaching staff will help the young players feel more comfortable. When he promoted a number of young players into the first team for the final game of the 2016-17 season, he asked academy chief Nicky Butt to sit on the bench.

5. What else does he need?

Mourinho has signed three players this summer -- Fred from Shakhtar Donetsk, Diogo Dalot from Porto and Lee Grant from Stoke. However, there will be very few United fans who feel that is enough to bridge the gap with Manchester City, who have splashed £60 million on Riyad Mahrez from Leicester. There are question marks at centre-back, left-back and up front, and Mourinho will have to decide what else he needs. He faces a race against time with the Premier League transfer window due to shut before the start of the season -- almost a month earlier than last summer.