Had Atlanta tanked #5 in the east in my season preview before the season started...Don't know if that qualifies as "contender" in your mind. But while we're talking, why don't you go ahead and look up the 2014-15 Cavs as well as the 2012-13 Lakers...
There are no contenders in the East outside of Cleveland and no, #5 in any ranking doesn't qualify as a contender.
The 2012-13 Lakers weren't a contender. They were the 8th seed. The Cavs were the exception that proves the rule.