The 21-year-old midfielder made 30 appearances and scored twice for the Chairboys this season across all competitions.
After joining Palace in January 2022, Phillips slotted seamlessly into the Under-21s side. He then went on a half-season long loan to Shrewsbury Town in January 2023, winning their Young Player of the Year award.
The Republic of Ireland U21 international will now be part of Barry Robson’s side as they aim to finish in the top half of the Scottish Premiership before the mid-season split.