And this Sunday Leinster take on the Ospreys in the RaboDirect PRO12 final hoping to become the first side since Wasps in 2004 to do the double.
Thorn, who arrived on a short-term deal from Japan back in March, has been an integral figure in the season run in, making seven appearances in all competitions.
And Murphy admits that the team will struggle to replace such an influential figure, both on and off the pitch, when he returns to the Fukuoka Sanix Blues after this weekend.
"Brad has been fantastic, he's really added to the team in this close of the Heineken Cup, we brought him in for this three-month period and it's really paid off for us," Murphy told the Leinster club website.
"There is stuff going on in the background regarding next year and who's going to take on his role.
"It might end up with Brad coming back at some stage but at the moment he's contracted in Japan and we'll have to say good bye after Sunday.
"But he's had an amazing influence on the squad and fitted in really well so definitely from a Leinster point of view we would be delighted to see him back.
"All the guys have recovered well and there's no-one who played at the weekend who's going to be out of the Rabo final this weekend, we need to work hard now to make sure we're prepared."
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