Allrounder Hilton Cartwright has produced the goods with the ball after star WA paceman Jhye Richardson was cut down by injury during the Sheffield Shield clash with Tasmania at the WACA Ground.
Richardson scored a handy 34 on Sunday before snaring the wicket of Tim Ward for a duck in the dying minutes of the opening day.
But the 25-year-old couldn't take to the field on Monday after suffering a back spasm during the warm-up.
The Warriors remain hopeful Richardson will be able to play a role during the final two days of the match, but a lot will depend on how he pulls up on Tuesday morning.
The setback is yet another unlucky blow to Richardson, who has been plagued by shoulder injuries over the past few years, and more recently was battling a side strain and an ankle complaint.
He was also struck in the abdomen by a rising Peter Siddle delivery while batting on Sunday.
In reply to WA's first innings total of 238, Tasmania were bowled out for 252, with Cartwright snaring a career-best 4-23 from his seven overs.
WA finished day two at 1-42 in their second innings, with Cameron Bancroft (12) the only wicket to fall.
"He's had a heat pack on his back the whole day to try to get himself going," Cartwright said of Richardson.
"He must be in a fair bit of pain to not even be able to come out and field.
"I've had a few back spasms in my time and they're not ideal to have, let alone trying to send it down at 140 clicks."
Cartwright took the key wickets of Ben McDermott (49) and Jordan Silk (47) among his haul, with Tasmania losing their last four wickets for five runs.
"It's a hard one to digest because my first few overs were a bit of junk," Cartwright said with a laugh when asked about his four-wicket haul.
"I was very fortunate to get the early wicket of McDermott, and then I just literally tried to do a job for the guys to get to the new ball, and the guys just nicked them for me.
"I just hung me and got a few rewards, which is really nice.
"I actually had a bit of a glute strain last game, so I hadn't even bowled at all in the week leading into this, so I went in very fresh and very nervous."
Tasmania nightwatchman Lawrence Neil-Smith overcame a blow to the helmet to top score with 60 in his side's first innings, while Beau Webster finished unbeaten on 53.
Up to 35mm of rain is forecast for Perth on Tuesday, while wet weather is also forecast for Wednesday, meaning a result is unlikely.
Australian Associated Press