The one player we haven't replaced yet from last season is Evan Turner. While there is reasonable optimism some combination of Rozier, Brown, Hunter, and maybe Jackson can approximate what Turner brought, Ainge has suggested he'd potentially like to add a ball handler, and there is one player who's probably on the trade market who can fill that role by himself. As the title suggests, that player is Tyreke Evans.
Evans is a point guard in a small forward's body, with a suspect outside shot (although he did make 38% of his threes last year in a limited sample). Undoubtedly he'd be able to step into Evan Turner's role on both ends of the court.
Meanwhile, New Orleans is moving on. Their free agent acquisitions have been a PG, SG, SF, and they drafted Buddy Hield. Evans is on the last year of his deal. His salary of $10.2 million isn't unreasonable, but it's possible New Orleans would like to spend that money differently. There are a few ways this trade could work.
Firstly, it's possible the Celtics could have enough cap room by just renouncing Zeller and releasing John Holland. However, it's unclear whether or not Ante Zizic is counting against the cap at this point, so I'm going to be conservative and assume that he is.
Therefore, the Celtics could renounce Zeller, release Holland, and trade James Young and a second-round pick to New Orleans. This would leave New Orleans with about $8.4 million in cap space to target another free agent. Evans could fit directly into our cap space (he has a $1 million trade kicker). The advantage of this would be that if we wanted to upgrade from Evans later this summer, we could include his $11.2 million salary in trades without any delay. The disadvantage is that we'd be pretty much out of cap room to sign our 2nd round picks, and therefore couldn't offer them three or four year contracts.
Alternatively, if the Pelicans are interested in Zeller, he could be sent along in a sign-and-trade himself. If packaged with Young and Holland, Zeller could be signed for a salary starting at just above $9.4 million to make salaries match. (If Young is excluded, Zeller would have to start at $13 million). The advantage for the Celtics in this instance is they'd be able to sign their second round picks with cap room before finalizing the trade. They couldn't trade Evans for 60 days, but that restriction still ends before training camp begins.
I mostly think Evans could be a productive player this season. If Rozier and Brown push him to the bench, that's no loss. If they aren't able to, then we'll be a better team with Tyreke. He won't get in the way of next year's free agency. And his salary would be enough to take on Gordon Hayward by himself if Hayward becomes available (meaning a trade of Tyreke and picks is possible), and is only a few hundred thousand less than what's needed for Cousins.
It's not the flashiest move, but acquiring Tyreke could a) help us this year, b) help us acquire a star-level player more easily, and c) not inhibit next year's cap situation if neither A nor B come to pass.