Doucoure was on a yellow card and was issued with a warning from referee Craig Pawson after committing two fouls.
The midfielder is still building his match sharpness, with just three starts to his name in 2024 - suffering an Achilles injury last November.
Alongside his yellow card, Doucoure was struggling to keep up with the pace of the game against Ipswich.
Explaining the decision to withdraw the £21 million Malian during the break, Oliver Glasner said: "We took him off because of the yellow card - he had one more foul [before a red].
"I remember we played at Chelsea, where Will Hughes had the same situation. He made one foul, and we were lucky that he did not get a red card.
"So, we decided at half time to make the sub. Also, you don't lose a window [if you make a change at the break]."
The Palace manager added that the club are supporting Doucoure to reach his former heights but admitted that it will take time.
"Usually, you say it takes as long as you are out to get back to your best shape. Cheick is working very hard on this.
"It's good that we are getting other players back to have options.
"He will get all the time and all the support. He's a great player and a great guy.
"It will happen. I don't know when, but we will see the best Cheick Doucoure we have seen. I want a better one than what he has been."