Sage said after last week's win at Fulham that Doucouré could feature against Middlesbrough in the Carabao Cup.
But illness kept the midfielder out of the 3-0 win against the Championship side, delaying his return after a lengthy lay-off.
In his pre-match press conference, Sage confirmed that Doucouré has now returned to training, but added that he would need to reassess the fitness of his squad following tomorrow's session.
“Cheick [Doucouré] trained yesterday and this morning," said Sage when asked for a team news update. "All will be good for him. He was a little ill, but no, he’s fine.
“We’ll see tomorrow because of the fatigue from playing Saturday and Tuesday night, so we have to check tomorrow.
“Today went well, but tomorrow will be better. Until then [tomorrow] we cannot give an accurate list."
Sage did confirm that Ismaïla Sarr won't be ready to return against the Tractor Boys.
"It's the same situation," Sage added. "He’s not with the team for the moment. I thought he could be with us in training on Monday, but it was not the case.
“We expect him next Monday to start training with the first-team. We want him on the pitch.
As previously stated by Sage, forward Jean-Philippe Mateta remains unavailable.
Crystal Palace v Ipswich Town
- Saturday, 12th September
- 15:00 BST
- Premier League
- Selhurst Park
- Live audio commentary on Palace TV+.