During Mourinho’s tenure, De Gea, Sergio Romero and Joel Pereira were all ahead of Henderson in the goalkeeper pecking order.
Pereira was seen as De Gea’s long-term successor, whilst the latter was sent on loan to Grimsby Town and Shrewsbury Town.
United have released Pereira, now 24, this summer after failing to impress Solskjaer during his time at the club.
Meanwhile, Henderson’s confidence has been publicly documented, so Mourinho’s account of their exchange at United doesn’t surprise.
Many United fans expect the England international to play as Solskjaer’s first-choice goalkeeper next season.