The Newcastle medical staff were unable to pop Gidley's shoulder back in at the ground, with the No.7 taken to hospital for the painful procedure.
Buderus, who missed last weekend's City-Country match with the Achilles tendonitis injury, was unable to complete the first half before succumbing to his complaint.
The 34-year-old had been considered all but certain to be part of the NSW team for State of Origin I in Melbourne on May 23, to be picked in a fortnight.
But the veteran, who said he had taken part in just one training session since their round seven fixture against St George Illawarra 16 days prior, admits he is unsure of when he'll next take the field.
Jennings left the field in the 60th minute after pinching a nerve in his neck when he landed awkwardly on his shoulder while attempting to score a try.
The 24-year-old, who was given a dressing down by club management before the game for drinking on Anzac Day, was hopeful the injury wouldn't restrict him and said it was just a stinger.
"It's nothing too bad, well hopefully,'' he said.
"When I did it I thought I had done my shoulder. As time went on it kind of went away (and) I started to get confident.''
Bennett admitted the loss of his captain for the season soured what had been Newcastle's most impressive offensive display of the season.
"But it's football. It goes with the territory,'' he said.
The Knights, spurred on by a pumped up Willie Mason in his first NRL match since 2010, dominated the contest down the left flank, with James McManus, Timana Tahu, Zeb Taia and Jarrod Mullen all scoring from tries set up on that side of the field.
Mason joined the action in the 28th minute to massive applause from the healthy crowd and didn't wait long to make his mark, earning a penalty with his first touch of a 21 minute stint.
Penrith ended a drought of their own in the 24th minute when Jennings scored out wide, their first points in 202 minutes of NRL football.
They didn't have to wait quite as long for their next points - with Newton scoring a second half double, but it was never going to be enough with Neville Costigan scoring late to put the result beyond doubt.
Penrith halfback Luke Walsh suffered a suspected medial ligament knee injury and is expected to be sidelined for up to six weeks.
- AAP