Per Sports Illustrated's Chris Mannix:
"The Celtics front office was looking for a way to get out from under that contract, and ultimately were not able to do that despite having conversations with multiple teams over the last several months. I was told they discussed a deal involving Kemba Walker and LaMarcus Aldridge when Aldridge was still in San Antonio. Primarily because Aldridge was on the last year of his contract, whereas Kemba Walker has two years currently and about $76 million remaining on this contract. That frustrated Kemba Walker ... so for Kemba to hear his name and understand his name was in trade rumors, that absolutely has frustrated him over the last six to eight months."