The Sharks are sweating over the fitness of Bok Tendai Mtawarira, following the news that prop Dale Chadwick has suffered an injury setback.

Sharks coach John Plumtree confirmed that the 23-year-old could miss the start of the season.

"We've lost Dale [Chadwick] for four to six weeks with a stress fracture in his foot," Plumtree told the Sharks' website.

"We can't afford to have any upsets with Beast [Mtawarira] now, we lost him for a long period last year.

"So there is a little bit of pressure there, but I am excited about Allan Dell, he's a good young prop coming through our system."

The concerns over Mtawarira stems from a long-standing heart conditions which required medical procedures on more than one occasion in the last couple of years.

The player is suffering from an intermittent irregular heart rhythm, which forced him to return home to South Africa from the Springbok touring squad in November.

This followed his withdrawal from the Test against Ireland in Dublin as a precautionary measure, after he had a recurrence of mild heart palpitations.

Mtawarira had previously undergone a similar medical procedure when the condition flared up during a Super Rugby season.

“I am well, so there is really no need to worry,” Mtawarira said after the procedure last year.

“The procedure went well. It’s only a minor procedure and sometimes it needs to be done more than once to clear the palpitations. This is something that has happened to me before and that can be treated. Also, it’s not career-threatening.

“Sometimes I get quite excited before a game and that is probably what triggered it."

Apart from the issue at loosehead prop, Plumtree is confident that he has adequate cover in the squad.

"If you look at our squad, there is good depth in the backs, good depth in the locks now, good depth amongst the loose forwards; there is really good competition for places and with the two trial games coming up in February, we'll get the opportunity to see how everyone performs," he said.

"This year, in comparison with previous years at this point in time, from a fitness point of view, we've lost a key player in Bismarck du Plessis for a period of time which isn't great, he's a big part of our planning and our game plan as well. It obviously puts pressure on the team without him, but it then presents an opportunity for others to step up."

In terms of squad depth, The Sharks have options all over the park to the extent that any injuries should not prove as catastrophic as they may have in the past.

They have lost very little, gained two in Butch James and Franco van der Merwe, with the bulk of the squad now very experienced.

"Butch and Franco have done well," explains The Sharks coach of the newcomers to the team. "Franco is really enjoying it here, although it is different to what he is used to, but he looks to have settled in nicely. Butch knows our system, knows how we operate here and it's really just coming back to family for him.

"He's been great."