"I will say this: I'm hearing Boston is feeling really, really good about their chances of getting him", Haynes said on SportsCenter.
Until then, the Heat, Celtics, and Jazz franchises (and their fans) will have to nervously await Hayward's announcement.
The small forward appeared in 73 games last season, averaging 21.9 points per game to go along with 5.4 rebounds, 3.5 assists and 1.0 steals.
But Hayward to Boston changes everything, with the Celtics now primed to push the Cavs team that has reached the Finals in three consecutive Junes since James' return from Miami.
Hayward's max deal with Boston will come in at $127.8 million over four years.
It also is the second straight summer that the Celtics have successfully recruited a coveted player on the free-agent market. Isaiah Thomas and Al Horford were also on hand to help recruit Hayward to Beantown.
Hayward's 8,077 career points rank eighth in Jazz history. Now he's added an All-Star without surrendering any picks or young players.
Two league sources immediately confirmed that Celtics president Danny Ainge had not, in fact, heard from Hayward.