Boston Celtics president of basketball operations Danny Ainge doesn't know if All-Star big man Al Horford would have stayed with the franchise had he known Kemba Walker was going to come to Boston.

Horford signed with the rival Philadelphia 76ers after opting out of his 2019-20 player option with the Celtics. Horford probably had an idea Kyrie Irving was leaving Boston, but the center likely didn't know Walker had eyes for the Celtics.

“I don’t know that Al makes the decision he makes if he knows that Kemba’s coming. I have no idea,” said Ainge, via Ben Rohrbach of Yahoo Sports. “That’s how free agency is. You try to make decisions before you know other certainties. We got two new guys who chose to come play for us, who really want to be here, and we wish them well. We’re grateful that Al and Kyrie chose Boston, and we’re grateful for all that they gave us.”

Al Horford signed a four-year, $109 million contract with the Sixers — $97 million of the deal is guaranteed.

The Celtics obviously would have loved to bring Horford back and pair him with Kemba Walker, but like Danny Ainge said, it's time to move on and look toward the future.