Injured Springbok scrumhalf Charl McLeod has been ruled out of the Sharks' Currie Cup encounter with the Pumas in Durban on Saturday.
McLeod, who injured the AC joint in his shoulder in the 39-27 win over the Blue Bulls last Saturday, may miss more than just one match through injury.
However, prop Eugene van Staden (elbow) and loose forward Jean Deysel (thigh) are expected to be fit - although the latter sat out training on Tuesday.
Meanwhile Sharks coach John Plumtree insists his team are "not quite there yet" and must improve their attacking game if they are to mount a serious defence of their Currie Cup title.
The Durban side claimed an impressive 39-27 victory over the Blue Bulls at the weekend, their second win over their Pretoria rivals this season.
"We still feel we've got a lot to do," Plumtree said.
"We're still seeking that game that we really want to play.
"We saw touches in the last week, which was great, but we still feel that we're not quite there yet."
Plumtree was particularly concerned by the work rate of his defence, and for the second week running he highlighted the importance of refining that area as they prepare to welcome the Pumas to Kings Park on Saturday.
"There are so many areas of our game that are good," he said.
"But we made 208 tackles against the Bulls last week, and they made 70, so physically we know if we don't turn that around by the end of the Currie Cup, we could be wearing ourselves out a bit.
"We're not over-structured in attack at the moment. We'd like to get a little bit more discipline with what we're doing in attack.
"We got a little bit going last week, but then the Bulls would give away a penalty.
"Obviously we were quite dangerous with turnover ball and some of the tries we scored last week were really good, but we don't really feel that we're there yet."
Plumtree's men are well placed for a home semi-final, with four of their remaining six games to be played in Durban, including visits by the teams above them on the log, Western Province and leaders the Golden Lions.
They have faced their toughest challenges this season, however, from the smaller unions.
They only just pipped the Pumas in their first game in Nelspruit, while they struggled at home to the Leopards and were also beaten by Griquas in Kimberley.
Plumtree said the game plan for this weekend's clash had been discussed at length.
"We've been talking about it so much, we're actually sick of it," he said.
"So it's really up to the players now, and we haven't talked about it at all this week.
"They're growing as a group and hopefully they'll show some maturity and respect for the opposition and also hopefully they'll come with the right attitude."
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