But three games into the campaign rival fans mocked and pundits have questioned the signing, suggesting Zabaleta - who turns 33 in January - was past his best following the club's dreadful start to the season.
A change of formation have made West Ham more solid of late, though, and Zabaleta has been at the forefront.
The right back may not have the pace and engine he once possessed as City's marauding fans' favourite.
But he has been proving the doubters wrong with superb performances as West Ham have slowly edged their way up the table.
And according to Opta Zabaleta is the best defensive full-back in the entire Premier League with 15 tackles so far, putting him ahead of his expensive replacement Kyle Walker and the likes of Manchester United's Antonio Valencia and even Chelsea's Cesar Azpilicueta.
It's not just his tackling and performances that have endeared him to Hammers fans, though.
Just like at City, where he was adored by supporters, Zabaleta's spirit and passion has been a huge part of his charm and was on full display when West Ham scored a last gasp goal to beat Swansea City last time out.
Indeed that coupled with his performances makes him an early frontrunner for the club's prestigious Hammer of the Year award.