Summary
Powell has had a bit of an up-and-down career, as the 4-year, $42 million extension that he signed back in 2017 has gone back and forth between looking like good value and bad value for the Raptors. Powell was excellent in the '19-'20 season, helping the Raptors surprisingly grab the #2 seed in the East after losing their starting wings from their championship run in Kawhi Leonard and Danny Green.

Powell was one of the best 6th man of the year candidates in '19-'20, and was traded to Portland mid-way through this past season. While his outside shooting has remained reliable at a really good 41% each of the last three seasons, his scoring was down a bit this year along with his finishing rate at the rim.

Powell isn't much of a playmaker, so as long as he's hitting shots and giving enough effort on defense, teams will value him this offseason. Most teams will see him as a starting-level wing, or at least a really high-level backup, and could pay him like one.
 
Cap Considerations
Powell has an $11.7 million player option for 2021-2022 that he is likely to decline. If Powell does opt out, he will be an unrestricted free agent with a $16.4 million cap hold and full Bird rights. Since his cap hold is likely above his market value and the Blazers will likely be operating over the cap anyway, his cap hold really isn't that relevant.

Powell will likely demand a starting salary of more than the full $9.5 million Non-Taxpayer Mid-Level Exception, which means only teams with cap space will be able to sign him. If Powell and an over-the-cap team have mutual interest, sign-and-trade options can be explored.