Marler can return for Quins’ Champions Cup trip to Racing 92 on Sunday, after his two-week ban for verbally abusing Bristol’s Jake Heenan.
Marler was mortified by making comments about Heenan’s mother only to realise that the Bristol flanker’s parent was unwell in hospital.
The 32-year-old has been chastened by his suspension, and was relieved that Heenan accepted his apology.
Now Quins head coach Matson hopes the front-rower can put the incident behind him on his return to action.
“His close friends have checked in on him and put an arm around him, but he wouldn’t want everyone doing that,” said Matson.
“Joe’s one of the most protective guys in our team, so if someone’s feeling low, or in the doldrums, he’s the first guy to go and look after them.
“I clearly have a rose-tinted glass, but he’s great for our club and he’s great for our game, because he is a character and he is a bit old-school.”