Zamora scored a dramatic winner in the playoff final against Derby County last Saturday, but he will be forced to find a new club unless QPR place a new offer on the table for the forward.
"I don't think it's a case of whether he can still do a job," Onuoha told reporters. "He can comfortably play in the Premier League.
"I would love to see him stay, not just from a personal perspective because he's a good friend of mine, but from a professional one as well because he's one of the most difficult players to defend against."
Zamora joined QPR from Fulham in January 2012.