It's unclear when Ridley specifically suffered the injury, as he finished Week 4 with his most productive rushing total during the 2013 season.
With Ridley out, the Patriots could turn to veteran LeGarrette Blount as their starter in the backfield. The former Buccaneer has averaged 4.6 yards per carry and had a standout effort against the Atlanta Falcons in Week 4.
Though Gronkowksi's questionable designation means he has a 50 percent chance of playing, one person familiar with the Patriots' thinking told ESPN NFL Insider Adam Schefter he's "not confident" the tight end will play this weekend.
Meanwhile, Amendola said on Friday that he's "looking forward" to Sunday, but would not indicate whether he will be available to play. He's missed each of the past three games while nursing a groin injury suffered in Week 1.
"Had a good day today," Amendola said Friday. "Had a good practice, ran around, made some plays and looking forward to Sunday, so we'll see."
The team is also dealing with other injuries to wide receivers, as rookie Kenbrell Thompkins (shoulder) and Aaron Dobson (neck) are questionable. Veteran Austin Collie was signed on Thursday and could make his debut this weekend.
Ridley is the only player the team has ruled out for Sunday, as wide receiver Matthew Slater is doubtful after participating on a limited basis during Friday's practice. Ten players in total, including linebacker Jerod Mayo and offensive tackle Sebastian Vollmer, are listed as questionable.