Snead cleared waivers and was outright optioned to Triple-A Tacoma on Saturday.
The Mariners designated Snead for assignment Tuesday.
The Mariners selected Snead's contract from Triple-A Tacoma on Wednesday.
The Mariners reassigned Snead to minor-league camp Wednesday.
Snead has signed a minor-league contract with the Mariners, Matt Eddy of Baseball America reports.
Oakland outrighted Snead to Triple-A Las Vegas on Friday.
Snead was optioned to Triple-A Las Vegas on Monday.
Snead (1-2) took the loss against the Mariners on Wednesday, allowing two earned runs on three hits and a walk over one-third of an inning. He struck out one.
Snead (1-1) took the loss against the Nationals on Sunday, allowing an unearned run on a hit and a walk without recording an out.
Snead (1-0) recorded the win over the Giants on Sunday, firing a perfect sixth inning during which he struck out the side.