1. CB Markell Sanders - Sanders was to be UM's one returning starter at corner, but he bolted in December. His early departure suggests it's possible he had decided to leave before Stitt was fired (& it was therefore unavoidable), but his reasons have never been revealed AFAIK.
2. QB Gresch Jensen - The defection you've probably heard the most about. Jensen threw for 2521 yards, accounted for 26 total touchdowns, and put up a 148 efficiency rating in 2017 as a RS-freshman. He was also a finalist for the Jerry Rice Award. Based on an interview with one of the Nuanez brothers on Missoula's ESPN Radio, it sounds like he was basically out the door after Stitt was fired and was just kinda going through the motions during Spring Ball (he announced his departure shortly thereafter).
3. DE Chris Favoroso - He had 13 TFLs and 6 sacks as a RS-sophomore last year, but just announced his intent to transfer earlier this week. He apparently wasn't going to fit in the new defensive scheme (it's rumored to be a 3-3-5) and there are multiple rumors about new DC Kent Baer being quite arrogant & dismissive toward him. Favoroso seems way too talented to just throw away, especially since he's already been offered a scholarship by an FBS school per his twitter account.