Henderson will kick-start his international career against the Barbarians in Wednesday's end-of-term rugby clash at Murrayfield.
Henderson started his international career with a try in his first Six Nations outing against Ireland almost two years ago - but failed to figure in the last campaign.
However, Scotland coach McGeechan insisted the shy powerhouse, who got the nod over Kevin Utterson, is ready to do his talking on the turf.
McGeechan said: "We examined the attributes of both players and reckon Andy deserves the place.
"He has been playing consistently and his selection reflects that. It is not just current form, it's also what each offers in the bigger picture."