The rift between Holding and Palace manager Oliver Glasner appears to be the root of the defender’s exile. When asked about Holding’s absence from the first team, Glasner offered a vague explanation, stating, "Rob is training individually at the moment. We will talk together – he knows the reason. But it is something that stays between Rob and me. Nothing public."
However, according to the BBC, the disagreement stemmed from a post-match running session following Palace’s 2-0 home defeat to West Ham on August 24. Holding was an unused substitute during that game, and it seems tensions flared in the aftermath, leading to his demotion to the U21s.