Casemiro's imminent arrival at Old Trafford will greatly enhance Manchester United's midfield options but will not resolve all of the club's problems.
That is according to former United striker Louis Saha, who also told Stats Perform that Cristiano Ronaldo was wrong to ask for a move.
Real Madrid head coach Carlo Ancelotti confirmed on Friday that Casemiro is set to leave the Santiago Bernabeu, with United reported to have agreed a £51million (€60m) fee.
Casemiro, a five-time Champions League winner with Madrid, is one of a number of midfielders to have been linked with the Red Devils.
Having appeared to have missed out on Frenkie de Jong and Adrien Rabiot, Casemiro's move to Old Trafford could be completed as early as this weekend.
While the Brazil international will bring a number of qualities to United, Saha believes his former side's issues run far deeper than simply bringing in a new midfielder.
United find themselves bottom of the Premier League for the first time since August 1992, which is the only previous occasion they lost their opening two games in the competition.
"It's a massive signing," Saha said. "But it is not a midfielder, it is not a striker, it is not a defender, goalkeeper or other transfers that are going to solve United’s problems.
"So don't be stupid in thinking, 'Oh, okay, we signed the big player who won the Champions League a few times, all our problems will be solved'.
"He'll really help the strikers to feel more confident that they have a certain kind of base that helps a team that wants to win titles. But he won't solve every player’s problems."
Casemiro is set to become United's fourth signing of the window following the arrivals of Tyrell Malacia, Christian Eriksen and Lisandro Martinez.
A number of first-team players have exited Old Trafford since the end of last season, meanwhile, with Paul Pogba the highest-profile departure to date.
The future of Ronaldo remains in the balance ahead of the September 1 deadline, although a number of teams have opted out of making an approach for the forward.
Ronaldo is reported to have asked for a transfer just a year after rejoining United, which Saha believes has left the Red Devils in a difficult situation.
"I respect so much Cristiano and I think he's in this bracket as such a special player that I completely understand the way to manage this is not easy," he said.
"Cristiano's a massive player and got 24 goals last year. That has a massive impact on the opposition because they fear him.
"It's a difficult position. But on the same terms, we can recognise that he has put the club in a very difficult situation, because he hasn't maybe spoken out at the right moment.
"I think the timing and the essence of this could have been kept a bit more private, until the deal is done or nearly done because of the respect that you have about the situation.
"The manager is trying to build a team, and you're saying you're unsettled and you want to leave. It's really hard. I don't think that he was right."
Ronaldo scored 18 Premier League goals last season – only Mohamed Salah and Son Heung-min (both 23) scored more – and netted a team-high 24 in all competitions.
Bruno Fernandes was the only other United player to reach double figures, finding the back of the net 10 times.
Saha, who won four trophies in five seasons with United, feels it is down to others to step up rather than Ronaldo if the five-time Ballon d'Or winner stays.
"He got 24 goals last season and shut all the criticism in terms of his personal ability, and that was in a team not playing well," Saha said.
"He is the only goalscorer who's got more than 10 goals, which is a joke. I mean, that's not normal.
"No other players could support when he wasn't scoring. We've seen bits from Bruno Fernandes, who is a bit of a shadow of the player he was before the arrival of Cristiano.
"The club and the other players haven't performed to facilitate a good rehabilitation for Cristiano Ronaldo's comeback."
