1. Donovan Mitchell agrees to 3-year extension with Cleveland Cavaliers
Believe it or not, there's a very good chance that Donovan Mitchell signing a three-year contract extension with the Cleveland Cavaliers ends up being the biggest move of the NBA offseason. Not only does it cement the Cavs as a contender in the Eastern Conference for the next few seasons, but it also puts teams like the Miami Heat, Los Angeles Lakers, and others at a potential crossroads in their respective builds. Teams like the Heat, Lakers, and even the Nets were waiting for their opportunity to make a move for Mitchell.
Once it became clear that Mitchell wasn't going to hit the trade block, each of those teams had to make a decision about their futures. The Lakers and Heat have not made any significant moves this offseason and the Nets pivoted toward an all-out rebuild. Heading into the offseason, an argument could be made that Mitchell was one of the bigger storylines.
Now that he has committed long-term to the Cavs, it certainly has created many shockwaves across the league.