Kyrie Irving isn't the only Celtics star (likely)leaving Boston this summer.

On Thursday it was announced that veteran center Al Horford would decline his $30.1 million player option for 2019-20, but it was believed he would ultimately sign a new three-year deal to stay in Boston. However, The Boston Herald's Steve Bulpett later reported that Horford and his team were no longer discussing a new three-year deal to stay with the Celtics, and that he now plans to sign a four-year deal with another team. 

Horford, 33, spent the last three seasons with the Celtics. Although his 13.5 points and 7.0 rebounds per game don't necessarily jump off the stat sheet, he was an invaluable piece to Boston's success over those years. 

According to Shams Charania, the Celtics are now preparing for a "strong scenario" that both Horford and Kyrie Irving will be signing elsewhere this off-season. As basketball fans know, Irving has been linked to the Brooklyn Nets. There have also been reports that the All Star point guard has "ghosted" the franchise since the season ended.

The New York Times' Marc Stein reports that Horford "already knows" that he could receive a four-year deal worth more than $100 million once free agency begins on June 30 at 6pm ET. 

Scroll down for some of the latest reactions to the unexpected Horford news.