Gallagher arrived in SE25 on loan from the Blues, but has not yet had the opportunity to feature in a competitive matchday squad.
Palace take on Brentford in Vieira’s first league match at Selhurst Park, and the manager said: “[Gallagher] is going to be in the squad. I’m looking forward to Conor’s first game for us. He’s somebody that will bring us different strength. He had a really good week so will be in the squad tomorrow.”
He also discussed fellow recent addition Joachim Andersen, who earned his first competitive minutes in a Palace shirt last week.
Vieira said: “That will give us more flexibility having those players getting fitter. It was nice for Joachim to play half an hour against Chelsea. That was his first game since the Euros and he’s in really good shape. It gives us options and flexibility at the back.”