Summary
After shooting over 40% from three each of the past seven seasons, Redick only hit 37% this season. The fit in New Orleans did not go as well as expected, and the Pelicans ended up trading Redick to Dallas, where he didn't have a major impact.

Because Redick still has the reputation of being an elite shooter, teams still respect him, so having him on the court provides some spacing and his gravity can free up openings for his teammates. Bigs will often get an open role to the rim simply by setting a pindown for Redick, as the fear of giving Redick any space can cause both defenders to go to Redick.

His age will certainly play a factor in his free agency, as Redick will turn 37 this summer. If his shooting woes end up being due to actual decline rather than just a slump, teams may be worried about signing Redick, especially to a multi-year deal.

Cap Considerations
Redick will be an unrestricted free agent with a $19.2 million cap hold and Early Bird rights. As his cap hold exceeds the salary he will get in free agency, his cap hold is not really relevant. If the Mavericks re-sign Redick, his cap hold will be replaced by his starting salary, and the Mavericks may still have some cap space depending on what happens with their other free agents.

If the Mavericks operate over the cap, his cap hold won't be relevant either. The Mavericks could offer Redick a starting salary of up to $22.4 million using the Early Bird exception, which is more than enough should they wish to bring him back.

Other teams will have multiple ways to sign Redick as even teams without cap space could possibly use either of the Non-Taxpayer MLE, Taxpayer MLE, or possibly even the Room MLE to sign him. There's also a chance that Redick only gets minimum-level offers this summer.