Although NBA free agency doesn't officially start until Sunday evening, some of the biggest deals to come this summer are already in place. The Boston Celtics are involved or connected to both signings.

As Kyrie Irving leaves Boston after two seasons, the star point guard is set to sign a max contract, four years $141 million, with the Brooklyn Nets. The 27-year old Irving averaged 24 points, 7 rebounds and 7 assists per game last season for the Celtics and his signing with the Nets signals the start to D'Angelo Russell's unrestricted free agency.

As one point guard leaves Boston, another arrives. According to multiple reports, Kemba Walker is headed back to the New England area where he won a national championship for UConn. Walker is expected to sign a deal similar to Irving's in Brooklyn after he averaged 26 points per game for the Hornets who drafted Walker in 2011.

What about Kevin Durant? Torn Achilles and all, the gem of 2019 free agency, is said to be interested in meeting with four teams: Knicks, Nets, Clippers and Warriors, who can offer the two-time NBA Finals MVP more money than any other team.

I use the phrase "gem of 2019 free agency" in reference to Durant, but maybe that title should be reserved for Kawhi Leonard after what we saw in the postseason leading the Raptors to a title. Leonard's list of landing spots could include Los Angeles (Lakers or Clippers), the Knicks and a return to Toronto.