In 1988, he joined ESPN, where he served primarily as an in-studio analyst. During the baseball season, he appeared nightly on Baseball Tonight and had regular spots on SportsCenter, ESPNEWS and ESPN Radio. He wrote an Insider column for ESPN.com and also wrote for ESPN The Magazine. The Globe reprinted some of his ESPN columns well into the 1990s. In 2006, Gammons was named as one of two field-level reporters for ESPN's Sunday Night Baseball, joining Bonnie Bernstein. He held that position through the 2008 season, when he moved exclusively to baseball.
After 20 years with ESPN, on December 8, 2009, Gammons announced that he would leave ESPN to pursue "new challenges" and a "less demanding schedule". Gammons joined the MLB Network and MLB.com as on-air and online analyst.
This Rawlings official MLB baseball was signed in blue by Gammons and includes a JSA sticker and COA.