The person spoke on condition of anonymity because no details of the probe have been revealed publicly.
The Warriors declined to match McCaw's offer sheet almost seven months after rejecting their $1.7 million qualifying offer and two-year, $5.2 million deal, which included a non-guaranteed deal his second year.
As Medina noted, Marc Stein of the New York Times reported that the Warriors offered no response to a question about the Cavs' move.
However, McCaw played in only three games with the Cavaliers, averaging 1.7 points in 17.7 minutes, before Cleveland released him Sunday.
How long the league's review will take has not been determined, nor is it clear what the Warriors might be seeking. Eventually, the Cleveland Cavaliers extended McCaw a two-year, $6 million non-guaranteed contract.
Stephen A. Smith thinks Ravens should have played Joe Flacco
Jackson was the team's leading rusher with 54 yards on nine carries but failed to eclipse 200 yards through the air. Replay official Terri Valenti will work the Colts-Chiefs game in her first playoff assignment, also making history.
Patrick McCaw entered this past offseason as one of many restricted free agents that figured to have a hard time finding a deal they wanted with so many teams unable to create cap space to bring in new players via free agency. "I don't know that there's been a totally non-guaranteed offer sheet before".
Shooting guard Patrick McCaw appeared in three games this season, all with the Cavaliers.
At least four teams are reportedly interested in signing McCaw, while the Cavaliers may also want to bring him back.
McCaw is now slated to become an unrestricted free agent.