Portis told 106.7 The Fan on Tuesday that he's awaiting the results of an MRI on his left groin, which he injured in Sunday's 17-12 win over Philadelphia.
"I don't think the team would even let me attempt to go and try to play on Sunday," Portis said. "But who knows? ... I'm going to take my time and make sure I'm healed."
Portis said Sunday he felt a "pop" in his groin before leaving the game.
"It's bothering me," he said Tuesday. "It's stiff."
Portis has only 195 yards on 49 carries this season. His playing time was already on the wane with the emergence of Ryan Torain, who was promoted from the practice squad two weeks ago.
Torain ran 18 times for 70 yards and a touchdown against the Eagles.
Portis missed the last eight games of last season after suffering a severe concussion in a helmet-to-helmet hit.