Castro is not expected to travel with the team for their Absa Premiership clash against Free State Stars at the Goble Park Stadium on Tuesday evening.
Amakhosi have confirmed that the Colombian hitman has been ruled out after picking up an ankle injury in their previous encounter against Cape Town City.
The 29-year-old was replaced by Bernard Parker inside 35 minutes at the Cape Town Stadium over the weekend, and is now undergoing medical treatment.
Castro has been instrumental in the Chiefs attack this season, chipping in with three goals and two assists, alongside former Mamelodi Sundowns strike partner Khama Billiat.
Meanwhile, defender Eric Mathoho, who did not feature in Solinas's squad on Saturday, is also set to miss tonight's clash with Ea Lla Koto due to a groin strain.
The club have also advised that utility midfielder Joseph Molangoane is progressing in his recovery after suffering a broken leg in their cup tie against Stars earlier this season.
'Tight' is said to be doing strengthening work in the gym.
Kick-off of this evening's match is scheduled for 19h30.