As per reports, the duo do not share the best of relationships and have been involved in several altercations throughout the season.
The decorated midfielder, who is currently on loan from European champions Real Madrid, hasn't featured for the Bavarian outfit
Speaking after one of the team's training sessions in Dubai, the Croatian briefly discussed the attacking midfielder's role at the club, refusing him a free pass into the first team.
"I am delighted to have him around. I know he is a top player and I am aware of what he can do. But now, he must show that he deserves to be considered as a starter. I expect him to be decisive for us," Kovac said, as quoted by Live Soccer TV.
Kovac's side are currently six points behind league leaders, Borussia Dortmund and the former Croatia boss admits he will need to get the best out of his players to cut the deficit.
"We finished the first half of the season strong, and we have top-calibre players in each position. We will have a tough time getting back to the top spot, which is why I will need James and everyone else to show all their skills," Kovac concluded.