James Harden, player option
The way James Harden has operated over the last few years, it would be surprising if he didn't opt out of the final year of his contract to sign another deal with (probably the LA Clippers), or another team. If he does opt out, he'll technically have the chance to sign with any team he wants, but I'd argue that he's one player that most teams across the league should try to steer clear of. For several reasons, Harden, at least at this point in his career, should be considered a huge risk as a free-agent signing.
Harden is coming off another solid season for the Clippers, but the signs of Father Time are clearly in his game. He's going to be 36 years old at the start of next season and maybe has another high-quality year or two before we begin to see him truly tail off. The good news is that his game has been aging well because of his 3-point shooting ability and the tendency to get to the foul line. But any team openly giving him $30-plus million or more per season for more than one year would be making a huge gamble.
Khris Middleton, player option
Even though I find it hard to believe that Khris Middleton would opt out of $34 million next season, there's at least a small chance he does elect to do that with the hope of landing a multi-year contract this summer. Again, with the way injuries have taken a toll on his career of late, it may be in the best interest for Middleton to take the one-year big payout, but you never know. Maybe there is a team that is willing to take a chance on a two-year deal for Middleton.
If Middleton does end up opting out of his contract and hitting the open free agency market, I tend to believe that there are many teams that should avoid going down this path with Middleton, even if the money isn't that much of an issue. Even if Middleton would take a bit of a pay cut for a multi-year deal, he still hasn't proven the ability to stay healthy, and that would be a risk that could blow up in a team's face this offseason. That's the biggest reason I'd say there's buyer's beware with Middleton this summer.