Summary
After some poor stints in Phoenix, Washington, and Sacramento, Ariza looked like he might be done being a legitimate rotational player on a good team. However, after being traded to Portland in 2020 he started playing much better, looking more like the two-way wing that helped the Rockets compete at the highest level against the Warriors at their peak.

However, Ariza missed the 2020 playoffs with Portland because he sat out the Orlando bubble, and was only okay for the Heat in the '20-'21 season. The Lakers hoped he could be a solid 3-and-D forward for them in '21-'22, but he was unable to stay healthy and wasn't particularly good when he did play.

Ariza is not the athlete he was in his prime, but he's still mobile enough to defend adequately on the perimeter. However, he hasn't hit shots at a high enough level to be a real threat on offense, hitting under 32% from three over the past two seasons, and just 26% in '21-'22 alone. Since Ariza's role on offense has become primarily a spot-up shooter, that's a problem.

Given he will be 37 years old when free agency rolls around, and considering he wasn't able to be a quality rotation player for the Lakers, Ariza may not have a ton of interest in free agency. I think he can still stick around in the NBA for maybe a little longer, but he is probably nothing more than a minimum-level player now.
 
Cap Considerations
Ariza was waived by the Lakers near the end of the '21-'22 season. Teams will have multiple ways to sign Ariza as even teams without cap space could possibly use any of the Non-Taxpayer MLE, Taxpayer MLE, Room MLE, or Bi-Annual Exception to sign him. It's also likely that Ariza only gets minimum offers.