Western Force coach Simon Cron says his team won't be fooled into complacency after the Chiefs made a whopping 11 changes to their starting side for Saturday night's clash in Perth.
Callan was rushed to hospital on Saturday night after injuring his neck while making a tackle in the opening minute.
The 38-year-old's return has been etched into Force folklore with Thrush scoring the winning try in a 34-27 win over the Melbourne Rebels.
The Western Force's forward stocks have been given a big boost after signing Wallabies enforcer Isi Naisarani for the remainder of the Super Rugby Pacific season.
The Western Force's struggles in New Zealand have continued with a 30-17 loss to the highly professional Blues.
Force fullback Chase Tiatia has relished the chance to rekindle his bromance with Toni Pulu, and he has plenty of love for the rest of the team's backline as well.
The Western Force have pulled a selection surprise by naming Saracens halfback Gareth Simpson for his Super Rugby Pacific debut - and it all began with a Zoom call on Christmas Eve.