Dallas Cowboys wide receiver Brandin Cooks will miss at least one game after he developed an infection in his right knee after undergoing a minor procedure, .

Cooks, who has been battling a knee issue since training camp, underwent a knee procedure after their 20-15 win over the New York Giants last Thursday. Cooks had the procedure done in New York, and then he developed symptoms after returning to Texas. Cooks has since undergone a second procedure to clean out the infection in his knee.

It’s unclear how long Cooks will be sidelined, but he will miss at least Sunday night’s game against the Pittsburgh Steelers. Specifics of the initial knee procedure aren’t known, but Cooks underwent a similar procedure during training camp and did not experience any infection issues as a result.

Cooks had a single catch for 16 yards in the Cowboys’ win over the Giants last week, which brought them to 2-2 on the season. The 31-year-old has 91 yards and a touchdown on nine catches this fall, his second in Dallas. He had 657 yards and eight touchdowns on 54 catches last season. Cooks is in the final year of a two-year, $39.7 million deal.

The Cowboys will now have to lean even more on star wide receiver CeeDee Lamb with Cooks out. Lamb, who signed a new deal with the team after holding out during training camp, has 316 yards and two touchdowns through four games.

The Cowboys will take on the Steelers in Pittsburgh next on Sunday night. The Steelers, behind backup quarterback Justin Fields, are 3-1 so far this season and are coming off a 27-24 loss to the Indianapolis Colts. The Cowboys will host the Lions on Oct. 13 before their bye week, which could give Cooks extra time to recover should he miss more than just a single game. Dallas is also dealing with injuries to star defensive players Micah Parsons and this week due to a foot injury.