The running back posted on Instagram Thursday in response to his injury.
"Thank you Lord for the ups and downs, the highs and lows and everything in between," he wrote. "Thank you for all the prayers and well wishes! I love this game and there's no quit in me! #IWillBeBack. 'I can't surrender, I don't know how to!' - Captain America."
According to Voth, Whittaker suffered the injury in a "noncontact, on-field drill during Phase 2 of the offseason program" on Monday.
Whittaker, 29, rushed only seven times for 18 yards in a backup role last year. For his career, he's posted 615 rushing yards and two touchdowns while catching 68 passes for 552 yards and another four scores.
Whittaker contributed in other areas, however, as Joe Person of the Charlotte Observer noted:
With Christian McCaffrey entrenched as a key playmaker and Carolina having signed C.J. Anderson this offseason, Whittaker likely would have battled for the third-string spot with Cameron Artis-Payne and Elijah Hood. That leaves the Panthers with solid depth in his absence.