Carrick must buy a new left-back! Manchester United's "Carlos" faces serious doubts after being dismantled by Amorim's tactics.

In Manchester United's final preseason friendly against AC Milan, 31-year-old Luke Shaw played the full match, but his position was brought into question. The "English Carlos" was exposed under the targeted tactical attacks of former manager Ruben Amorim, and Carrick can no longer ignore the need to refresh the left-back position.

Amorim said when he took over Manchester United that the club must suffer to have a chance to return to glory. He used AC Milan's relatively modest squad to make life difficult for Manchester United, especially for Luke Shaw. Although the Red Devils scored within two minutes, they eventually lost 2-4.

Manchester United's top priority this summer was to strengthen the midfield, but it now appears that solving the left-back issue is also urgent. Amorim exploited Luke Shaw's weaknesses using the 3-4-3 tactic that had been criticized at Manchester United, deploying a wing-back to torment him. Samuel Chukwueze, who was on loan at Premier League side Fulham last season, played as Milan's right wing-back. He first equalized by scoring a goal himself, then provided two assists to help the Rossoneri take the lead.

Luke Shaw was repeatedly drawn to the center by AC Milan, and his lateral movement back to the left was too slow to block Chukwueze's shots or passes. Amorim's tactical system shone in that position, and other Premier League teams may follow suit, using the same approach against United's defender next season.

The match against AC Milan was Luke Shaw's first full 90 minutes of the preseason and his first match in a week with two games. In his first complete match, he performed poorly in the hot weather. This serves as a reminder to Manchester United of the huge risk in relying solely on Shaw; although he is reliable, his stamina and speed are not what they used to be.

Luke Shaw, who has been at Manchester United for 12 years, may be entering his final season at Old Trafford. He clearly cannot carry the load alone and play a full season of matches. Last season, Shaw performed well, never got injured, and started all 38 league matches, but that was a one-match-a-week schedule, and this season will not allow such ample rest.

Manchester United correspondent Andy Mitten said: "I think left-back is a position that Manchester United is focusing on revamping. They want to complete a few signings before the transfer window closes. We already know that some names have been mentioned. I think Luke Shaw cannot handle the intensity of 50-60 matches next season, which is why Manchester United is trying to strengthen the squad by bringing in new players to compete with Luke Shaw. The challenge for Manchester United is how to convince the target players. Will they tell them they will definitely be starters? Actually, probably not. Besides the obvious financial issues, the club must also address this problem."

That is why Manchester United has scouted numerous potential left-back candidates. In the Premier League, there are Newcastle United's 21-year-old Lewis Hall, Arsenal's 19-year-old Myles Lewis-Skelly, Fulham's 28-year-old Antonee Robinson; in other leagues, there are Racing Santander's 19-year-old Jorge Salinas, RB Leipzig's 28-year-old David Raum, Club Brugge's 21-year-old Joaquín Seys, and others—nearly a dozen names.

Hall is Manchester United's primary target, but the club's first two inquiries were flatly rejected by Newcastle's hierarchy. Unless the 21-year-old Englishman forces a move by demanding a transfer and United's hierarchy makes a massive offer, any deal is extremely unlikely.

Meanwhile, 19-year-old Manchester United left-back Harry Amass is expected to be sold this summer. United's left-back depth is insufficient, with the only other option being 18-year-old Uruguayan youngster Diego León, who has not played any first-team matches.

British media reports that Manchester United believe Patrick Dorgu could become a left-back in the future, but Carrick now thinks he is better suited as a left winger. It is worth noting that the Danish hardman was Amorim's first signing for Manchester United, originally intended to replace Luke Shaw as the left wing-back.

Ironically, Amorim led Manchester United to 15th place but had greater spending power than Carrick, who led the team to third place. Last summer, Manchester United spent over £200 million on forwards, but this summer the club's transfer spending is less than £100 million.

Manchester United's summer transfer spending lags far behind its competitors, which will inevitably impact the season. Moreover, the Red Devils are the only one among the traditional Big Six Premier League clubs that has never spent over £100 million on a single player. This summer alone, Chelsea has spent £117 million to sign Morgan Rogers, Manchester City has spent £116 million to bring in Elliot Anderson, and Tottenham has spent £100 million to acquire Sandro Tonali.

Manchester United does need to address the "Manchester United tax" issue of paying inflated prices for players, but that should be done when the squad is already complete enough to withstand temporarily not buying. Now, United urgently needs a left-back and a hard-working, ball-winning defensive midfielder. While other clubs are spending big, Sir Jim Ratcliffe is calling for prudent spending.