The England international trained on Tuesday morning at Cobham but was left out of the squad for the match at Stamford Bridge the following day.
Palmer has had a stop-start season due to a recurring groin injury, but Rosenior has given a new reason as to why he is not available against Pafos.
It had previously been expected that the 23-year-old would be rested against the Cypriot champions or play only a fraction of the match.
Speaking to broadcasters before the match, Rosenior said: “Cole felt a little bit of tightness in his thigh.
“He just misses out, but he should be absolutely fine for Sunday.”
**Standard Sport** understands the player is carrying a minor muscle strain.
Chelsea face Crystal Palace on Sunday as they look to build momentum in the Premier League following Saturday’s 2-0 win at home to west London rivals Brentford.
Rosenior continued: “I’ve got to manage the squad as best as possible and make sure we are fit throughout the season with the sheer amount of games we’ve got in a short space of time.”