Mark Gastineau is suing ESPN ... claiming the network did irreparable harm to his reputation when it posted an edited video of his 2023 altercation with Brett Favre.
The now-viral incident took place in November '23 at a sports show in Chicago ... when Gastineau confronted the ex-Packers star about a 2002 sack he gave up to Michael Strahan that allowed Strahan to break the New York Jets legend's single-season record.