Newcastle Knights forward Jeremy Smith in strife for head slam tackle on Penrith Panthers' Matt Robinson Knights hang on to hold out Panthers by just two points. JEREMY Smith's chances of playing for the Kiwis in Friday's Test against Australia are in jeopardy after the Newcastle back-rower was placed on report following a head-slam incident last night. And the Knights could be without five-eighth Jarrod Mullen and veteran hooker Danny Buderus for lengthy periods with both set to undergo surgery. Buderus, who missed last night's win against Penrith, is in hospital and will have further surgery tomorrow to repair a disc problem in his back. He will miss up to six weeks. Mullen, who would have been chosen in the Country side today, will decide this morning after consultation with the club doctor whether to have surgery to repair cartilage damage in his knee. He seems certain to have the operation and faces four to five weeks out, which will put him out of contention for NSW Origin selection. Jeremy Smith was placed on report for this tackle on the Panthers' Matt Robinson. "I'll see how it pulls up in the morning and talk to the doctor and the club about it," Mullen said. But I'll probably have to get it done. It can't come at a worse time with the rep games coming up, but the club comes first. The knee keeps locking up on me and although I've been able to keep going, it's only going to get worse if I don't do anything about it. Smith has concerns of his own after a tackle on Matt Robinson midway through the second half left the Penrith forward heavily concussed. Robinson was taken from the field on a stretcher in a neck brace following the incident, with Smith put on report after appearing to slam his head into the ground. "He's not quite with us at the moment," Panthers coach Ivan Cleary said of Robinson. Asked if he had a view on the seriousness of the incident, Cleary said: "I'll leave it up to the powers that be." Smith is certain to be named in the Kiwi Test side today, but whether he plays against the Kangaroos in Canberra on Friday night is another question. Judging by video evidence, he seems certain to be charged by the match review committee and could face a stint on the sideline. Penrith's Matt Robinson is stretchered from the field. Knights coach Wayne Bennett did not want to comment, claiming he did not get a clear view of the tackle. In one of the worst games of the season, the Knights hung on for a two-point win despite the Panthers finishing the game with no one on the bench after a spate of injuries. They lost Wes Naiqama, Cameron Ciraldo, Josh Mansour and Robinson during a game in which they trailed 8-0 for a long period. Despite their setbacks, the Panthers gave themselves a sniff of victory when backrower Sika Manu pounced on a dreadful Darius Boyd error to score under the post with 11 minutes remaining. James McManus celebrates his try for the Knights. But the Knights hung on with their wingers Akuila Uate and James McManus their best players. "I'm not happy but pleased we've got the two points," Bennett said. It wasn't good. Cleary was more upbeat about the Panthers despite a fifth straight loss. Josh Mansour of the Panthers is helped off the ground by trainers after suffering an ankle injury. "I feel like that was the toughest we've played all year," he said. NEWCASTLE 8 (J McManus try K Gidley 2 goals) bt PENRITH 6 (S Manu try L Walsh goal) at Hunter Stadium. Crowd: 15,536.