More trouble or not? Why Randy Gregory and David Irving missed practice on Thursday

A normal Thursday practice became a mystery of sorts for the Dallas Cowboys with troubled defensive linemen David Irving and Randy Gregory both absent.

This is Irving’s first week back with the Cowboys after missing the first four games under NFL suspension for violating the NFL’s substance abuse policy.

And Gregory is in headed into his fifth game back since the season finale in 2016 after serving an indefinite suspension for repeated violations of the substance abuse policy.

According to a source, both should be available for Sunday’s game against the Houston Texans.

Owner Jerry Jones said Irving was tending a personal family matter, causing him to miss practice.

He had a strong day in first practice on Wednesday and if he returns to practice Friday he should be good to go for Sunday’s game, where he could play between 10 and 20 snaps in a rotation at defensive tackle.

“Conditioning is always going to be a factor, we got to see as the week goes on,” defensive coordinator Rod Marinell said. “But he is a terrific athlete. Great knee bend. He is terrific guy terms of rushing the quarterback, mobile, balanced. Perfect matchup.”

Gregory did not practice because he was in Chicago, according to Marinelli, meeting with the NFL’s medical director as part of his after-care program. He made a similar trip in August before the Cowboys played a preseason game in Houston.

Gregory should be back for practice on Friday and make the trip to Houston for Sunday’s game against the Texans, barring anything unforeseen.

Marinelli said the return of Irving should make for a terrific rotation up front as he would join Gregory, defensive end DeMarcus Lawrence, who leads the league with 5.5 sacks, defensive tackle Tyrone Crawford and defensive end Taco Charlton in getting after the quarterback on passing downs.

Irving, who had seven sacks in eight games last season, is the team’s second-best pass rusher behind Lawrence.