McMillon cleared waivers and was outrighted to Triple-A Lehigh Valley on Tuesday, Todd Zolecki of MLB.com reports.
The Phillies claimed McMillon off waivers from the Marlins earlier this month, but he'll lose his 40-man roster spot again with Philadelphia protecting some prospects from the Rule 5 draft. McMillon's career has been greatly affected by arm injuries, and he averaged 95.3 mph with his fastball in 2024 after he sat at 99 mph with the pitch in 2023.