Mathoho sustained a concussion after clashing heads with Platinum Stars striker Bongi Ntuli last week, while Xulu has suffered a groin strain.
"'Tower' suffered a concussion during the fixture against Platinum Stars last week,” Chiefs' physiotherapist David Milner explained on the club's website.
“We observed him after the collision. We gave him a few minutes in the second half but had to substitute him (55’) as a precaution.”
Long-term casualty Sibusiso Khumalo is still struggling with a knee problem, however, goalkeeper Brilliant Khuzwayo is recovering well from ankle surgery.
“We are happy with Khuzwayo’s progress to full fitness,” Milner added.