The Argentine-turned-Chilean had been frozen out at Upton Park, which led to his move from East London to West London on January 6th.
Yet with just 14 minutes under his belt for Harry Redknapp's men, Zarate is set to head back to Upton Park, with Carlton Cole on the verge of a move to West Bromwich Albion according to reports.
Zarate, who had a very public spat with Hammers boss Sam Allardyce before joining QPR, will now look to break into the West Ham side upon his return - but a different player could move to Loftus Road in exchange.
According to the Mirror's live transfer deadline day blog, winger Matt Jarvis will move to QPR in order to compensate for Zarate's departure.
Jarvis, 28, had started just one Premier League game for West Ham this season, and is unsurprisingly looking for first team football elsewhere.
QPR seem to be the favourites to sign the former Wolverhampton Wanderers winger, who will add some pace down the flanks for a Rangers side who need a spark in the final third.
It's a blow to lose Zarate, but Jarvis' potential arrival would be a smart move from manager Redknapp, who famously loves a deadline day deal.