Isle of Wight have signed Danny Stoneman on loan from Plymouth after Rikki Mullins ruled himself out of riding for the National League club.
Stoneman will make his debut for the Islanders in the first leg of their challenge fixture at Stoke on Saturday.
Islanders' co-promoter Chris Hunt said he was surprised by Mullins' decision.
Hunt said: "We had a call from Rikki to tell us that he won't be racing this year, Kevin [Shepherd] and myself are extremely disappointed with him."
Hunt continued: "We have quickly agreed a deal to bring in Danny Stoneman at reserve to partner Gary [Cottham], with thanks to Mike Bowden at Plymouth.
"With our first meeting this Saturday we had to move quickly."