The 32-year-old joined the Black Cats from Bury in 2018 and scored 28 goals in 124 appearances during his time on Wearside.
Maguire was one of several first-team players who weren’t offered a new deal at the end of last season when his contract expired.
The forward scored some memorable goals while at Sunderland, including a stunning strike against Portsmouth in the play-offs, and became a popular figure among supporters.
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Despite seeing his game time reduced in his final season at the club, Maguire still scored five goals and provided five assists in 33 League One appearances.
The player recently took to Instagram to post: “Thanks to everyone @sunderlandafcofficial for the past 3 years. I loved my time at the club and will always appreciate the support that was shown to me from the fans.”