James, who turned 29 on Sunday, has been left out of the squad for Madrid's last two matches, with Zidane saying on Friday that he "didn't know" if the midfielder would play for the club again.
Madrid go into the season finale on top of La Liga with 80 points, one ahead of Barcelona, and will play their last three league games in just seven days this week.
They started the hectic schedule with a trip to Granada on Monday before hosting Villarreal on Thursday and capping it off with a trip to Leganes next Sunday.
"James is an important player, he's always shown it," Zidane said in a news conference on Sunday. "It's his birthday so the first thing is to congratulate him.
"He's a member of the squad. It's true there are players who play more or less, but I won't disregard any player, they're all important. You'll see if he travels to Granada, but I'm counting on all the players I have."
The Colombia international -- who joined Real Madrid in 2014 and returned last year from two seasons on loan at Bayern Munich -- has been linked with moves to the Premier League and Serie A this summer.
James said he wanted to leave in 2019, with Atletico Madrid his preferred destination, before Real refused to sanction the move.