Worrall has been overlooked for South Australia's game against Tasmania starting Saturday as a precaution given his recent comeback from a back injury.

But prolific wicket-taker Chadd Sayers is set to return after having knee surgery last November.

The South Australian quicks, along with Victorian duo Chris Tremain and Scott Boland, are considered the pacemen most likely to break into Australia's Test squad for the Ashes series against England starting in August.

Worrall has missed a chunk of the Shield season because of back and foot injuries while Sayers was spelled in mid-November and had arthroscopic surgery on a troublesome knee.

Australia's vice-captain and SA's captain Travis Head says Worrall is likely to return to Shield action in the following round.

Worrall played in the Melbourne Stars' losing BBL final after being man-of-the-match in their semi-final win over Hobart.

But Head says the 27-year-old paceman isn't yet ready for the rigours of long-form cricket.

"It's more precautionary for Daniel," Head told reporters on Wednesday,

"His body is going good but we're going to make sure that we have him fit and firing for the (remainder of the) summer.

"He understands that. I'm sure there's now worries in making sure he finishes off the following three games really well and puts himself in (Ashes) contention."

Sayers, who has collected 259 first-class wickets at an average of 24.83, has long been touted as a potential Ashes tourist given his swing and seam bowling ability.

"If he can keep his body right, I don't think there's any question on his skill," Head said.

"I'm sure he'll take lots of wickets. The main thing for him is making sure he's really fit for four Shield games and then go from there."

Australian Associated Press