Philadelphia 76ers
Biggest mistake: Signing Caleb Martin to be the starting power forward
There's an argument to be made that the Philadelphia 76ers did an amazing job in prying Caleb Martin away from the Miami Heat in free agency. In a vacuum, that has to be considered a win. However, when you look at the details, perhaps it's not as great of a move as we all thought. Especially when you realize that the Sixers essentially promised Martin a starting job. From all indications, the early reporting suggests that Martin was signed by the Sixers with the intention of making him the starting power forward.
I hate play spoiler here but that role didn't exactly work out for Martin with the Heat and was one of the bigger reasons why Miami struggled so much defensively. It's not that Martin can't defend bigger players; he can. It's just impossible to ask him to do it consistently over the course of an entire season.
The Sixers would be doing Joel Embiid a disservice if they made him responsible for manning the defensive interior along with a 6-foot-5 power forward. I can't imagine this works out for long for the Sixers.