Shaw was criticised by Mourinho for the second time this season after the defender pulled out of the squad prior to the victory against Swansea City before the international break, due to not being 100 per-cent fit for the game.
Lallana defends Shaw
This led to many people questioning whether Shaw has a future at United anymore while Mourinho is the manager, but Lallana says that the defender's mental toughness should not be questioned.
When asked about the Mourinho's treatment of Shaw, Lallana said "I was with Luke Shaw at Southampton" and if anyone knew what he was like then Lallana did.
The midfielder went on to say that Shaw is a "very strong boy" who also recovered from a "horrific leg injury" that he picked up against PSV Eindhoven last year.
Lallana added that "you don't come back" from the injury Shaw had "without being mentally and physically strong" which is basically what Mourinho is saying he isn't with his public criticism.
The midfielder continued to say that you don't come back from an injury like that "without having difficult times mentally on your own", as it would have been difficult to be sitting on the sidelines for so long.
Shaw looking to prove Mourinho wrong
Now it is time for Shaw to show Mourinho that he has what it takes to be a United player, whether that been in training or on the pitch, as he will not want his United career to end due to this.
Shaw's time at United has been littered with injuries, but the defender was quick to show many fans on his social media pages during the international break that he is putting in the effort to be ready for the next games. He could be in with a shout to play this weekend against Arsenal at Old Trafford.