4 Defensive upgrades the Pistons could target this offseason

The Detroit Pistons have plenty of weaknesses they need to fix in the offseason if they want to have a chance to be competitive next season.

The defense should be atop the list, as the Pistons are 26th in defensive efficiency and allowing the most points per game in team history. Hopefully, the return of Ausar Thompson and Quentin Grimes next season will give them a boost, but Detroit still needs defenders on the perimeter and in the paint.

Here are four players with various contract situations who the Detroit Pistons could target as defensive upgrades this summer.

Detroit Pistons free agents and trades: 4 Defensive upgrades

Xavier Tillman: Unrestricted free agent

Tillman might have a little too much crossover with Isaiah Stewart as a big who can play either spot and is probably best as a small-ball center. Tillman doesn't put up big numbers but makes an impact on the defensive end, as he's 7th in defensive estimated plus-minus, a flawed but useful stat to judge defenders. Tillman would be cheap and add another versatile defender who has played in a winning environment.

Alec Caruso: Expiring contract, possible trade

I talked about Caruso as one of two possible trade targets from the Bulls. He's a tenacious and smart defender on the perimeter who was on the first-team All-Defensive squad last year and will be again this year. It doesn't hurt that he shoots 40 percent from long range, making him an ideal 3-and-D perimeter player who could help alter the shoddy defensive culture in Detroit, though what he will cost is a separate issue.

Jonathan Isaac: Pending

Isaac has a partially guaranteed year left on his contract next season at $17 million and it will be interesting to see what the Magic do. Isaac has played well in 51 games this season (1st in defensive EPM) so the Magic have a tough call, as they already have a lot of money tied up in bigs. Will they keep them all? If they pick up Isaac's contract, we could see Moritz Wagner hit the trade market instead and he would also be an option for Detroit. Isaac hasn't been able to stay healthy, but when he is, he's a 3-and-D big man who can defend. If he ends up a free agent, he's an intriguing one even though his health is a big red flag.

Isaiah Hartenstein: Unrestricted free agents

Hartenstein is a solid rebounder and defender for the Knicks and will hit the open market this summer, which is why he is one of my top free-agent targets for the Pistons. Detroit needs to upgrade their defense at center by jettisoning James Wiseman this summer and replacing him with a veteran who can defend and Harteinstein fits the mold. He won't break the bank and would give the Pistons a solid backup who has been playing for a winner.