Heaslip has seemingly been made of granite over the course of his career, but the No.8 missed time over the winter for both club and country due to injury.
His last GUINNESS PRO12 appearance came against Ulster at the turn of the year, while he is set to meet Scotland at BT Murrayfield this weekend as Ireland go for glory.
And he believes Scotland's Glasgow contingent - eight of their starting XV play for the Warriors - have already shown how lethal they can be in the GUINNESS PRO12.
"Down the spine of the team they have a lot of the Glasgow players who are with each other all the time in the PRO12 and they have a great relationship with each other," he said.
"We've seen some opportunities, and also some threats from them. They've a big mobile pack, especially the back five who are big units.
"We have to respect that threat. Their half-backs direct play well and the back five in the pack can mix up the work, a good ball-carrier and then off the ball guys who are abrasive in the ruck."
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