Cruz sent a series of tweets Sunday calling his message from a night earlier a "mistake," adding that he "never will advocate violence under any circumstances." The original message has since been deleted.
"I apologize, that's why I deleted it," one of Cruz's messages says. "I believe conversation not confrontation leads to change and progress."
Zimmerman, a former neighbourhood watch volunteer, was acquitted of second-degree murder in the shooting death of teenager Trayvon Martin after a three-week trial in Florida.
Cruz recently signed a five-year contract extension with the Giants reportedly worth $43 million.