Signing Arturo Vidal would, in one fell swoop, address Manchester United's biggest on-field issues. This single addition to the playing staff has the potential to indeed make United instant contenders again.
United's midfield malaise is well established. In the last years of Sir Alex Ferguson's reign at Old Trafford, fans jokingly wondered whether he was trying to pioneer a revolutionary new, midfield-free "doughnut" formation—so-called because of the great big hole in the middle.
It reached its lowest ebb on 31 December 2011, Sir Alex's 70th birthday, in a home game against Blackburn Rovers.
The game lives in some infamy, as Paul Pogba—speaking in a Canal+ documentary—cited the selection of Park Ji-Sung and Rafael da Silva ahead of him in central midfield as the moment he decided leave United (h/t ESPN.co.uk).
That a full-back and a winger formed United's core in the first half of that game showed just how serious the midfield problem had become.
It seems reasonable to suggest that last season was the first in five or so in which United's biggest issue was not, in fact, central midfield. Sir Alex's retirement and his poor choice of successor meant United's biggest issue was sitting on the bench or standing in the technical area.
However, that was not because the midfield issue had been significantly addressed, in spite of the signing of Marouane Fellaini. It was just that United had finally found a bigger problem.
Now that David Moyes has been replaced with a manager whose capabilities at the highest level are proven, United are once again left facing up to the hole in the doughnut.
The signing of Ander Herrera was the first step in filling that gap, but he cannot do it alone. He is a vital addition, but the problem is too big for one addition to solve.
This was highlighted when the group of 25 players United have taken on their tour of the USA was announced. It contains only three central midfielders: Herrera, Tom Cleverley and Darren Fletcher. Michael Carrick is injured and may be out for as long as 12 weeks, per BBC Sport.
Fellaini is not part of the travelling party, with the Daily Mirror suggesting he may have been given a break after being involved in Belgium's run to the quarter-final at the World Cup.
Neither Carrick, Cleverley, Fletcher nor Fellaini could claim to have had a good season last time out. Fletcher generally did well when called upon, but presumably due to the issues he has faced with illness, he was not called upon that often.
Cleverley's woes have been well documented, as has Fellaini's unimpressive start at United. Carrick managed just one goal and no assists in the league last year.
United do have other areas of concern, notably in central defence and in wide areas, but they are nowhere near as pronounced as the midfield problem.
Arturo Vidal is a one-man solution to this problem. His statistical output last season for Juventus was phenomenally impressive: 11 goals in the league and five assists. His defensive contribution included an average of 4.1 tackles per league game that compares favourably with Fellaini's 2.8, Cleverley's 2.2 and Carrick's 2.1.
United's midfielders' key pass numbers are perhaps last season's most damning metric. Carrick managed one key pass per league game, but for Cleverley it was 0.5 and for Fellaini a truly abominable 0.3. Vidal would be an instant improvement on this if he could match the 1.5 key pass per league game he managed.
Vidal would also add something that is very challenging to quantify in numbers. Of course, this is a fundamentally subjective point, but United's midfield has appeared to me to lack for both belief and leadership in recent years.
Vidal is a loud, demonstrative and visible presence in an area where United are in dire need of those things.
He would add goals, assists, tackles, leadership and presence. He is a player who appears to lift those around him. The highest praise I can think of is that he is the first player in a generation who has reminded me of Roy Keane at his best.
It may be a decade too late, but signing Vidal would mean that United have finally replaced Keane. In doing so, they would address their single most visible flaw and become contenders again.
All statistics per Whoscored.com.