The Stormers will face the Sharks without influential number eight Duane Vermeulen in Saturday's Super Rugby semi-final at Newlands.

Coach Allister Coetzee has opted not to risk his star loose forward, who reportedly made it through a semi-contact session on Tuesday without any complaints.

However it means hooker Deon Fourie will once again wear the number eight jersey after packing down at the base of the scrum against the Rebels two weeks ago.

"Deon and Duane bring something different from each other, they are very different players, but we have confidence in Deon as this is a chance for him to show his versatility against a very mobile Sharks pack," said Coetzee.

"I said earlier in the week that Duane had improved, and he had.

"But I thought about it and just felt in the end that it was too much of a risk to play him when he isn't completely ready. He is improving all the time and there is a possibility he could be available after this, but we are not thinking further than this semi-final.

"This is a big game against a very good Sharks team and if we don't win it there won't be any matches after this one."

Whilst the unavailability of Vermeulen is a big blow for the hosts, the return of physical lock Eben Etzebeth will give Stormers' fans plenty to smile about.

Etzebeth has recovered from an ankle injury that has kept the young Springbok sidelined since Super Rugby resumed after the June break. He will partner veteran Andries Bekker in the second row, which sees De Kock Steenkamp dropping to the bench.

"Eben was actually ready for the Rebels game but De Kock Steenkamp was playing well and we felt we could continue with him against the Rebels," said Coetzee.

"It will serve to motivate Eben to play even harder to know that even though he is a Springbok, he needs to retain the form that made him a Springbok in order to play for the Stormers."

In the only other change to the side that struggled to see off the Rebels a fortnight ago, Brok Harris replaces Frans Malherbe up front.

"When it comes to Brok Harris, we know we are up against an international class front-row on Saturday," added Coetzee.

"Frans Malherbe has been given game time and as a young player that has been great for his development. But where he has contributed best for us this year has been when he has come on late in the game, as he did when we beat the Sharks in the first round game here in February."

Stormers: 15 Joe Pietersen, 14 Gio Aplon, 13 Juan de Jongh, 12 Jean de Villiers, 11 Bryan Habana, 10 Peter Grant, 9 Dewaldt Duvenage, 8 Deon Fourie, 7 Rynhardt Elstadt, 6 Siya Kolisi, 5 Andries Bekker, 4 Eben Etzebeth, 3 Brok Harris, 2 Tiaan Liebenberg, 1 Steven Kitshoff.

Replacements: 16 Frans Malherbe, 17 Deon Carstens, 18 De Kock Steenkamp, 19 Don Armand, 20 Louis Schreuder, 21 Burton Francis, 22 Gerhard van den Heever.