Did ESPN pull out of doc on NFL & concussions due to pressure?

Here is ESPN ombudsman Bob Lipsyte (former star NY Times sports columnist) exploring why ESPN pulled out of its collaboration with PBS "Frontline" in producing a documentary on the NFL, football and concussions. The documentary was not going to portray the NFL put the Nat'l Football League in a good light, and the NFL is a key business partner with ESPN. They make huge profits together. Was the pull-out due to pressure from the NFL or from corporate parent Disney? A longtime ESPN journalist/consultant told Lipsyte that many ESPN journalists are "demoralized by the capitulation."