United took a low budget airline to go to Dublin before facing Shelbourne in a pre-season friendly with veteran coach Poyet, 41, due to play in defence because there are no other viable choices for Dennis Wise.
Heybridge Swifts keeper Gay, who was at Norwich as a youth, has been on trial and is the only fit stopper at the club.
So he has the chance to impress Wise along with Leon Constantine, David Prutton, Alan Thompson and Jamie Mullan, all waiting on contract offers.