The 30-year-old utility man lasted just 34 minutes in his first league start for 993 days following two cruciate ligament injuries, leaving the field in tears.
Alan Pardew: "We are sweating with Ryan.
"Fortunately, his surgeon was here in the stands today, he had come to watch from America, so he's gone with him to hospital with our doctor, and we are just fingers-crossed on that scan.
"He feels uncomfortable with his knee, so the win is sort of tinged with sadness because he is a person and a personality who just not deserve the trauma he has had already, let alone another trauma, so we are just fingers-crossed that he is going to be okay.
"I'm sure all our fans and certainly all the squad and the staff are just thinking about him at the moment."