Palmer has cut a frustrated figure this season, having had to manage a troublesome groin injury.
Speculation intensified about his future after he barely celebrated scoring a second‑half penalty against Brentford and went straight down the tunnel following Chelsea‘s 2‑0 Premier League win last weekend.
“There was frustration in the Brentford game – not because he isn’t happy here, but because he couldn’t perform at the level he wants to for the club,” added Rosenior.
“My job, and the club’s job, is to get him performing consistently at the level he wants to.”
Palmer missed Chelsea‘s 1–0 Champions League win over Pafos in midweek with a minor thigh injury, but the Blues boss said they “will assess his reaction to training” before Sunday’s trip to Crystal Palace.
Rosenior also confirmed number two goalkeeper Filip Jorgensen will miss out, although his injury is “not as bad” as first feared and he could be available for Wednesday’s Champions League game at Napoli.
Midfielder Dario Essugo will be sidelined “for over a month” after “slipping in training”.
