Summary
Collins had a very promising start to his career, but since then his career has been derailed by injuries. He only played in 11 games in '19-'20, and missed this entire past season as well.

Collins is similar to his surname counterpart who was also taken in the 2017 draft, John Collins, as he's a bit of a tweener between the four and the five. Collins demonstrates really nice verticality at the rim, which was a skill he had even coming out of Gonzaga. However, he hasn't quite developed the defensive instincts and awareness to be one of the better rim protectors in the league. He's also not a great defensive rebounder, finishing well below average for his position in defensive rebounding rate, per Cleaning the Glass. He's hurt a little bit by his skinny build, as he's not quite long enough to make up for his lack of bulk, in a way that someone like Rudy Gobert can.

On offense, Collins is a capable shooter, but his numbers certainly don't put fear into defenses, as his career three point percentage is under 32%. Collins does have promise as a big that can protect the rim, stretch the floor on offense, and also be a vertical lob threat. However, injuries and some lack of star upside could make teams pause before giving him a sizeable offer.
 
Cap Considerations
Collins will be a restricted free agent with a $16.2 million cap hold and a $7 million Qualifying Offer. Collins's QO could come into play if he doesn't get much interest as a restricted free agent this summer. If Collins isn't happy with any of his offers, he could end up taking the QO and trying again as an unrestricted free agent in 2022.

If a player has a smaller cap hold than his starting salary, his team can use cap space to sign-free agents before using Bird Rights to re-sign its own free agents. Since the Blazers will most likely not have cap room, Collins's cap hold will not play a factor. Although the Blazers will have full match rights on Collins as a restricted free agent, re-signing him for a big contract could push the Blazers into the luxury tax, depending on what happens with their other free agents.

For other teams, Collins will likely be looking for multi-year contract at least in the $10+ million range, and it would likely take something near that in order for Portland to not match. In addition, adding a 15% trade bonus, a player option, and some advances on his salary could make it more difficult for the Blazers to match.