Right back Ashby arrived at St. James' Park from West Ham United during the January 2023 transfer window.
Born in Milton Keynes, Ashby - whose father, Barry, played for Watford, Brentford and Gillingham - came through the youth ranks at West Ham, making seven appearances for the Hammers before joining the Magpies.
Ashby spent the 2023/24 on loan at Championship side Swansea City, where he made 16 appearances and scored once.
The 2024/25 campaign saw the defender sent on loan to Queens Park Rangers in the second tier. In 2025/26, Ashby was playing at Bradford City in League One.