Kanter, 27, agreed to sign a two-year, $10 million pact with the Boston Celtics on Monday. He averaged 13.1 points and 8.6 rebounds per game in 23 games last season for the Blazers. Kanter joined the team in February, after being waived by the New York Knicks.
"I was considering signing with the Blazers but they gave me only six minutes to make a decision," Kanter wrote in a text message to ESPN. "I felt pressure. And didn't feel comfortable. So I told him I need to think about it so I can call my brother so he can ask my family."
Kanter said the Blazers "kept pushing" before he "told them no."
Blazers star Damian Lillard commented on the situation Monday on Twitter.
"Sometimes there's a chance you lose out on two people because you're waiting on one," Lillard tweeted. "What I can confirm is that my boy was not given six minutes lol ... he was probably down to six minutes from the original 45 [minutes]."
Lillard also said he "was there."
"I was there," Lillard tweeted. "45 minutes ain't that long either but nobody [wants to] be left empty handed."
Kanter is averaging 11.9 points and 7.6 rebounds per game for his NBA career.