The 27-year-old was drafted by the Philadelphia Flyers in 2007 and has since gained significant experience in the AHL, ECHL and CHL in North America.
Head Coach Danny Stewart said: “Klotz is an important signing for us – he provides us with presence and further depth in the line-up and will complete our fourth line.
“He’s a tough character and hard-working guy. I felt it was important to add this element of toughness to our line-up to prevent any teams coming into our barn and taking liberties on our guys.
“There were times last year in Coventry where some of our better players had to get involved with some tough boys and that shouldn’t happen.
“In saying that, we wanted a guy that would buy into what we wanted do and not be a distraction. Garrett is that guy.
“He knows the role and he doesn’t make it about him. He’s a team first guy and we will also expect him to play as well.”