Only if you can parry (sorry, Monks!), and only if it's feasible to let the mob wail on you for awhile to get it to proc. As a non tank the raid belt's nice, but the uses can be a bit more limited, especially when comparing it to a 1) cast an undead conversion nuke and 2) hit an AA scenario. That being said I always thought Tendon Slice was way too strong for a passive proc, especially as a tank. Overly strong passive abilities are bad, mkay.
