Dallas Cowboys receiver Brandin Cooks will miss the game against Pittsburgh with a knee injury, adding a key offensive piece to the list of players out, along with pass rushers Micah Parsons and DeMarcus Lawrence. Coach Mike McCarthy declined Wednesday to discuss the details of Cooks’ knee issue beyond confirming he wouldn’t play against the Steelers on Sunday night. Cooks has been dealing with knee issues since returning to training camp but hasn’t missed any time. His absence could lead to the debut of rookie receiver Ryan Flournoy, who has been inactive for the first four weeks. The 31-year-old Cooks is in his second season with the Cowboys. He has nine catches for 91 yards and a touchdown. Cooks started each of the first four games along with All-Pro CeeDee Lamb and Jalen Tolbert. Second-year receiver Jalen Brooks or KaVontae Turpin could start, and both are likely to end up with more targets in Cook’s absence. Parsons hasn’t officially been ruled out but is expected to miss a game because of injury for the first time with the Cowboys after sustaining a high ankle sprain in last week’s 20-15 victory over the New York Giants. Lawrence sustained a foot injury against the Giants, and will miss at least four games after going on injured reserve.