Crystal striker Jordan Ayew will be available for Liverpool's game in the English Premier League on Sunday after returning to training on Friday.
Ayew had been on international duty with Ghana at the Africa Cup of Nations in Cameroon but returned to England following the Black Stars’ exit from the tournament.
The 30-year-old leaves teammates Wilfried Zaha and Cheikhou Kouyaté in Cameroon with Senegal and Ivory Coast respectively.
Discussing whether Ayew is ready to start after his involvement, Vieira said as reported by the club's official website: “We don’t know, we still have a couple of days before the game. He was in today and took part in the first part of training.
"We will have a discussion tomorrow [Saturday] to find out how he’s feeling."
Ayew has made 20 appearances across all competitions for Crystal Palace, scored one goal and provided two assists so far this season.