Park has been informed he will start the season at Triple-A Las Vegas, although the transaction has yet to be made official, Athletics team reporter Jessica Kleinschmidt relays.
Park signed a minor-league deal with the Athletics on Nov. 20.
Park cleared waivers and was outrighted to Triple-A Gwinnett on Thursday.
Atlanta designated Park for assignment Wednesday.
Hoy Park was traded from the Red Sox to Atlanta on Friday in exchange for a player to be named later or cash considerations.
Park was designated for assignment by the Red Sox on Tuesday to clear space on the 40-man roster for new signing Kenley Jansen, Chris Cotillo of The Springfield Republican reports.
Park was traded from the Pirates to the Red Sox on Wednesday in exchange for minor-league pitcher Inmer Lobo, Chris Cotillo of MassLive.com reports.
Park was designated for assignment by the Pirates on Tuesday.
The Pirates optioned Park to Triple-A Indianapolis on Monday.