These are things about Rudy Gay.
1. He is a small forward. That is the Kings' most weak position by far.
2. He is well-paid. He is due $37 million over the next two seasons.
3. He is widely overestimated as a scorer. He averages about 18 points per 36 minutes (strong), but does so inefficiently as compared to other top scorers. He has never registered a True Shooting percentage above .550, and has been above .540 only twice in seven seasons. The lower efficiency is due to a lack of propensity to draw fouls and inconsistent three-point stroke.
4. He is not reputed to do many other things exceptionally well.
5. Over the last few seasons, the Grizzlies are typically better when Gay is on the court than when he is not. But the margin varies between negligible and decent. And this does not account for a fairly strong starting lineup and weak bench over the Grizzlies' recent success.
Reports have suggested that the Grizzlies are among the teams that have expressed interest in former Memphis Tiger Tyreke Evans. Reports have also suggested that the Kings have checked in on Gay. But this isn't the right path for the Kings. Ignoring the potential sale of the team and the low likelihood the Maloofs would tack on a huge salary liability before finalizing a deal, it's just not a great match.
There are some items in a deal's favor: the aforementioned Sacramento weakness at small forward, the potential for Evans to become quite expensive in restricted free agency in July, the Kings' logjam in the backcourt. But Gay is just the wrong player for Tyreke. Evans is roughly the same level of scorer as Gay: about 18 points per 36 minutes, subpar efficiency. Evans' issue is a lack of a jumper; he gets to the line plenty, but his field goal percentage is perennially lower than you'd expect from a drive-first guard. But that's where the fair comparisons end. Tyreke is a far better passer, positional rebounder (meaning that Evans is a plus rebounder at two-guard while Gay is average at SF) and a defender of huge potential. Tyreke isn't perfect by any stretch. He might never be an All-Star. But right now, he's a better player than Rudy Gay.
And he's surely not going to be as expensive. Gay signed a max second contract when he hit free agency. (The Grizzlies let him get to restricted free agency, but then offered the max before anyone else did. Welp.) There's no scenario in which Evans draws a max offer from another team. Okay, the only scenario in which Evans draws a max offer from another team is if he wins a couple of Player of the Month awards in the remainder of this season. In which case, sure, give him the max.
Further, thanks to the new CBA, Evans' contract will include smaller annual raises and a shorter term, which really reduces a big deal's imprint. Evans is almost assuredly going to have a better deal than Gay when this is all over.
And the Kings could still trade Evans elsewhere for a better, cheaper player or prospect. Gay's just not the right call. This is one of those situations where while we all wish the team's owners would have invested in the team, this would be a counterproductive investment given the cost of giving up Evans.
So, no, I don't want the Kings to trade Evans for Gay. It'd be a bad deal, even if you attach the Kings' worst contracts (which honestly aren't that bad).