Domingo had initially joined City without them paying a transfer fee for his services following his unceremonious exit from Raja Casablanca in the Morocco Botola Pro League due to financial strains.
The 29-year-old was one of the first few signings by the Citizens last year with then coach Eric Tinkler attempting to assemble a formidable squad that would challenge for the Betway Premiership title.
Domingo was indeed a key player for City throughout the campaign, featuring in a total 32 matches in all competitions under Tinkler, who was later sacked and replaced by Mushin ErtuÄral and the club ending off the season with Roger de Sa and Diogo Peral in charge.
City were relegated after failing to save their topflight status in the relegation/promotion play-offs last month.
Their place was taken by newbies Orbit College from North West, who finished top of the round-robin league ahead of both City and Casric Stars.
It was immediately clear then that City would struggle to keep their big-name stars given the drop to the Motsepe Foundation Championship, which significantly reduces the monthly grant from R2-million to R500 000.
City have already lost goalkeeper Darren Keet and Lorenzo Gordinho as free agents and now Domingo has joined the growing list.