They haven't struggled to win games through their health concerns. So they are more justified in ignoring them. The Grizzlies health concerns has landed them a low playoff seed 2 out of the last 3 years.
Its been a concern for them over the last 3-4 years when it comes to the playoffs. They lost to an overachieving Portland team last year (who was worse than the team we beat) because CP3 and Blake went down in Game 4. I also think they've had the luxury of having at least 1 of Blake or CP3 playing throughout the season when the other player was out. i.e. Blake's great year in 2013-14 when CP3 missed 20 games, CP3 playing all 82 when Blake missed 15 in 2014-15 and we all know what happened last year.
We've had health concerns every single season, but we've still been able to remain a .610 win % team in all of those years.
I'm in agreeance of the injury concerns, but I think its being overblown. I don't think it should be used to justify a team's ranking for next season unless its guaranteed a particular player is out for the year.
Its a lot of people (or at least through NBA conversation) who think Conley is actually coming off a serious injury as well.