Manchester United did not have a great pre-season and in the absence of many of their stars due to injuries and post World Cup vacations, it was tough for a confirmed first 11 for the whole of the season to take shape.
United's transfer business so far has been poor as well. United have added Diogo Dalot, Fred and Lee Grant so far, out of whom, only Fred has realistic changes to start this season in the first team. Diogo Dalot is currently injured and will most certainly be an understudy to Valencia for the majority of the season. Lee Grant will be the third choice after Romero.
Manchester United are looking to add at least one central defender and one right winger before the end of the transfer window. While a lot of names are doing the rounds, Alderweireld of Tottenham seems to be the most likely defender to join, with a deal set to be finalized between the two clubs.
The situation with the right winger is not so clear, as there is still uncertainty about any potential arrival. The Willian saga has been dragged on for ages it seems, but apart from a lot of contrasting reports, nothing concrete has materialized so far.
Mourinho has said that he would prefer 2 more signings, but 1 would still be okay. That 1 signing now looks to be Toby Alderweireld and as such there might not be any reinforcements for the right wing this time.
However, in the event that no further players are added in the transfer window, Manchester United do still have a decent squad for the 2018/19 season and this is how they would most probably line up if no new players join before the closing of the Transfer Window.
Goalkeeper
There are no doubts in this position and it is also the strongest area for United. David De Gea had a poor World Cup where he let in 6 goals in 4 games, including that howler against Portugal.
De Gea is better than what his World Cup performance concluded and he will be desperate to put all those disappointments behind him and have another stellar year.
He finally won the coveted Golden Glove last season, a prize that he has deserved for quite a few years now, but which had eluded him since joining United. That will definitely inspire him to put on an even better performance in the games ahead.
United fans bemoan the lack of transfer activity, but they forget that keeping De Gea off Real Madrid’s clutches has been a coup of sorts for United and with the best keeper in the Premier League and arguably, the best in the world right now, protecting them in goal, Manchester United should have the confidence at the base of their team.
Defence
This has been the cause of concern for Manchester United in the preseason. They have been poor, and a lot has been written about defensive reinforcements, but the real picture, if statistics are to be considered, is quite different. Manchester United played 38 games and conceded only 28 goals, the second lowest in the league after Manchester City.
They also had 19 clean sheets, the most in the Premier League last season. In the Premier League alone, Manchester United had 564 tackles, with a tackle success rate of 65%. There were 481 interceptions and 853 clearances.
Only 4 errors led to goals in the whole season. Manchester City, the eventual champions, had 18 clean sheets and let in 27 goals. In the premier league, City had 563 tackles, with a tackle success rate of 68% and they had 346 interceptions and 588 clearances. Incidentally, they committed 6 errors which led to goals.
As such, even without the addition of further players, United should be fine. Lindelof had a stellar World Cup and should be building a formidable partnership with Bailly, who is one of the best defenders in the Premier League.
Valencia and Young will be the first choice in the wings initially, but Luke Shaw will eventually make the left-back position his own. Dalot might require a bit more time to take Valencia's place, but United's first choice defence in the 2018/19 season should be Valencia-Bailly-Lindelof-Shaw.
In case Mourinho wants to shift to a 3 man defence, which he most definitely will in big games and crucial away matches, Smalling might come in along with Lindelof and Bailly.
Midfield
United are spoilt for choice in the middle, but a closer look will reveal that the competition for the first team is between 5 players. This is because Mourinho likes a 3 man midfield and on current form and tactics, the players who are most likely to be shuffled around are Pereira, Herrera, Pogba, Matic and Fred.
However, the 3 man who will most likely make up the Manchester United midfield will be Paul Pogba, Nemanja Matic and Fred. Matic and Fred will most probably shoulder the lion's share of the defensive responsibilities, leaving Pogba free to join the attack and control the proceedings.
With the arrival of Fred, this season should be a breakthrough for the French World Cup winner. Last season, Pogba was strangled by Mourinho's defensive requirements, but with Fred likely to partner Matic as the deep-lying playmaker, Pogba should be looking ahead.
Also, Fred, as he showed in the preseason, can play at various positions in the middle, which should free even more space for Pogba to weave his magic.
In case of injuries, or if Mourinho wants to change things a bit, Pereira is more than capable to fill the deep-lying playmaker role and he and Fred did display the signs of a budding partnership during the preseason.
Ander Herrera is also another option, who can mix things up and perform a "job" as his manager demands. Additionally, McTominay and Fellaini also provide ample cover, abet not so much creatively. However, the Manchester United's strongest midfield this season should contain Fred, Matic and Pogba.
Attack
United are leaning on the left side when it comes to attack, with most of their attackers, barring Lukaku, preferring the left position. Sanchez is the first choice down the left right now, but Rashford and Anthony Martial also fit in there fine. Both youngsters can fill in for Lukaku down the middle as well. It is on the right that most of United's problems lie.
However, in the absence of reinforcements, Mourinho might be tempted to tweak things a bit, to make United a force to reckon with. Lukaku is untouchable as the front man, the focal point in the attack. Sanchez could be shifted to the right, a position he has played at during his time at Barcelona.
This would enable Rashford to come in on the left, a move that would benefit all parties. Rashford has recently been upgraded as the new No. 10 for United and he joins a long line of fabulous players who wore the famous number. It shows the confidence his manager has in him and Rashford should be using that as an inspiration this season.
However, if Mourinho does not want to shift his charismatic no. 7 to the right, Mata or Lingard or even Rashford could do a job there as well. In any case, the strongest United attacking line up should feature Alexis Sanchez, Marcus Rashford and Romelu Lukaku.