Cats prop Heinrich Kok has been ruled out of the Super 12 game against the Highlanders at Ellis Park on Saturday.

Kok starred in the Cats win over the Stormers at Newlands at the weekend, but injured a tendon on the inside of his elbow.

The extent of the injury was not known on Monday afternoon, but according to a Cats spokesperson, the prognosis isn't good. The Cats hope that the former Border and University of Stellenbosch player will only be out for a maximum of three to four weeks, but the possibility exists he may miss the rest of the Vodacom Super 12.

Kok got rave reviews after his solid performance on Saturday and coach Laurie Mains heaped more praise on him. "I watched him play for Border on a number of occasions last year. He was a hugely influential figure in a pack who did well without any big names and I realised his potential," Mains said after the game.

Former Eastern Province strongman Baksteen Nell should be the favourite to take Kok's place against the Highlanders' All Black front row of Carl Hoeft, Anton Oliver and Kees Meeuws. If Kok is ruled out of the rest of the competition, Pietman van Niekerk should get the nod as second loosehead prop in the squad.

Springbok wing Chester Williams is back and ready to be considered after he had minor surgery to his knee two weeks ago. He is, however, expected to start from the bench as Dean Hall and Wylie Human have done nothing to warrant a demotion. Hall was impressive with the scraps of possession he received, while Wylie showed he has what it takes to play at this level despite not seeing much ball either.

"Chester is not short of match fitness. He played in two of our warm-up games and the Sevens and will be ready for this weekend," Mains said.

Word from the Cats camp is that utility back Conrad Jantjes won't be considered for the Super 12 game this weekend, but should rather get more game time for the Lions. Jantjes played 20 minutes for the Lions in the Vodacom Cup this weekend after being out of action for a month due to hamstring problems.