Crothers leaves the Neuven Stadium after making 136 appearances, making him their longest serving player. He scored 16 times during his tenure at the club.
He joined Avro on an initial one-month loan in January, but has agreed to cancel his contract with Boro to join the NWCFL Premier Division side on a permanent basis.
On his move, Avro FC manager Alex Frost said: "Getting a player of Matty’s calibre to come and join us on loan is one thing, but for him to be prepared to lose out financially by making this commitment speaks volumes for the group which we have here right now, and we are all delighted that he has made this decision.
"His quality is obvious, particularly as far as his set pieces and his final ball are concerned - he has added a new dimension to our attacking play, and we are thrilled that he has enjoyed being with us as much as we have enjoyed having him."
Photo credit: Radcliffe
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