The National League North club have lost their summer signing with days to go before the big kick-off.
In an announcement on the club’s website, Agustien’s exit was confirmed.
But it appears the club are not far away from some new arrivals.
Club secretary Adam Etheridge said: “It’s disappointing to lose a player of Kemy’s experience and ability, but we have a number of signings that we are close to that we think will soften the blow.”
Nuneaton begin the season away to newcomers Ashton United on Saturday.