64/70/69/53 doesn't average to over 70 but it's close enough to the 70 ballpark.
But I don't know if the injury prone thing is really a fair label for Tanev, as this is usually reserved for players who are fragile in some manner and I don't think that apples to him. I mean you could say Vancouver's defense as a whole is 'injury prone'. From these past 4 seasons, the only dman to play a full 82 games was Luca Sbisa last season. Hell Keith Ballard was an ironman when he came to Vancouver, then quickly turned into a broken mess.
I mean if you look at Tanev's 2013-14 season, what prevented a full season was missing 7 games with a broken thumb and then the final 11 games with a broken finger. That's not really 'injury prone'. This past season, his lowest GP total as a regular, he missed 3 games from food poisoning and 2 games from the mumps.
The rest of his injury chart is either undisclosed or the ambiguous upper/lower body, so it would be up to any inquiring team to get the full details on those too see if he has a lingering issue or has just been unlucky. Otherwise there's no reason why he couldn't play a full 82 games, same as any other player.