New Zealand-born Roots, who qualifies for England through his English father, has played 55 times for Exeter, scoring 10 tries.
Exeter director of rugby Rob Baxter feels the forward is one of the club’s “most influential players”.
“He’s really back to his absolute physical best, dominating some games with his collision quality and the work-rate he’s putting in around the field,” Baxter added.
“He’s one of those players that we can build a really successful side around.
“He’s been key to the squad so far this season in what has been, so far, a good start to the season for us.
“We’re really looking for him to be at the heart of the squad to be really challenging for honours as we go through the rest of this season and in future seasons.”
