Defensive problems - but Manchester United had the second-best defence in the league last year?
Jose Mourinho has built a team at Manchester United that is defensively solid because he can coach that level of discipline to any players and subsequently get them to implement it successfully.
At United, he has a side capable of defending, but at the cost of attacking. This is because the likes of Phil Jones and Chris Smalling can't be relied on individually, which sucks the rest of the team into the art of defending to compensate.
As a result, United are perceived as the most boring of the elite Premier League sides, simply because their approach to football is defence-first. The Portuguese, of course, has always been a pragmatic coach, but at Old Trafford it seems to have evolved to the next level with mundane performances and a lack of creativity hampering the Red Devils' chances of competing.
The resolution? Buying defenders that Mourinho can trust to do a job and not rely on the rest of the team focusing their efforts on keeping the ball out of the net. But is Bonucci the man to do it?
What would he bring?
At 31 years of age, Bonucci has a wealth of experience, including a dominant period at Juventus where he helped guide the team to 12 trophies in just seven years. He and Giorgio Chiellini created a formidable defensive partnership that was the envy of virtually everyone in world football, so much so that AC Milan bought him.
International recognition has followed Bonucci as well, and he has played 80 games for his country, proving himself as a formidable defender in the process. But, there must be a reason why Juventus allowed such a class defender to leave last summer.
His performances over the last couple of seasons have not reached the levels that he established during his superb first few years at Juventus. At AC Milan, too, Bonucci struggled to dominate in the way he did in Turin.
For example, Bonucci's 30 tackles were the eight-most at Milan, less than attacking midfielders Hakan Calhanoglu and Fabio Borini, though his 51 interceptions and 22 blocks were the most of all his teammates. He still, therefore, is willing to through his body in front of anything.
Nonetheless, Bonucci failed to make the impact Milan desired when he was signed over the summer, proving that one man alone couldn't revolutionise the defence.
Is he a good fit at United?
Could Mourinho get Bonucci back to the form he once showed at Juventus? Well, if any manager could, it would be him.
Although the likes of Jones, Smalling and Victor Lindelof are under-performing - which is down to Mourinho's management - Bonucci is naturally of a better quality to those already in the ranks and his reputation would make him the best on the books at Old Trafford.
In terms of character, Bonucci is perfect. He's no-nonsense, gives very little away to opponents and epitomises bravery and determination, two key mental attributes sought after in centre backs. He also brings with him organisation and a style of leadership that raises the game of those around him - something United's defence lacks.
Approaching the twilight of his career, Bonucci still has a few seasons left at the top level, though he is untested in the fast-paced nature of the English game. And whilst he'd represent a short-term fix, it means he doesn't boast longevity. A valuable signing, but perhaps not one that would have a marked long-term impact.