FRISCO, Texas -- Last season, DeMarcus Lawrence became the first Dallas Cowboys pass-rusher since DeMarcus Ware in 2011-12 to post back-to-back double-digit sack seasons when he finished with 10.5.

Over the past two seasons, only Chandler Jones (30) of the Arizona Cardinals has more sacks than Lawrence's 25.

Randy Gregory entered 2018 having played in just two of the past 32 regular-season games because of multiple suspensions for violating the substance abuse policy. He finished the 2018 season with six sacks, second best on the Cowboys to Lawrence. His six sacks would have tied for the team lead in their other most recent playoff seasons (2014 and 2016). Also, the Cowboys were 6-0 in games when Gregory had a sack last season, according to ESPN Stats & Information.

As the Cowboys get ready for 2019, they cannot be sure when either will be on the field individually or collectively.

The Cowboys placed the franchise tag on Lawrence, guaranteeing him at least $20.5 million in 2019, but a source has said he will not show up for the offseason conditioning program, organized team activities, minicamp and training camp. Theoretically, he could miss regular-season games, too. He needs shoulder surgery as well, and there is no telling when he will undergo the operation, which could require a three-month recovery.

"DeMarcus has been a great player for us," coach Jason Garrett said. "He, too, has been a great leader, setting the pace for the guys on the defensive line, but really throughout the defense and throughout our team."

Gregory was suspended indefinitely by the NFL last week for violating the terms of his reinstatement. That Gregory became such a reliable pass-rusher after missing most of the previous two seasons was surprising. That he is in this current state with the NFL is not.

While possible he could return in time for the regular season, the Cowboys have to prepare as if they won't have Gregory. At least that's how they should go about it.

"I am by no means in any way weary or discouraged," owner and general manager Jerry Jones said. "As a matter of fact, with his contributions he made last year, although we would have liked to have had more but what we did get. The impact he made was there. It did nothing but encourage me to help him in any way we can to have a good career. He is a relatively young guy. For what he plays and what he has been through at this position, he is relatively healthy. He is a guy we can invest some of our time in to help us win."

Sure, but availability matters, and the Cowboys don't know when they will have their top pass-rushers on the field.

How does that Cowboys' pass rush look now?

Tyrone Crawford was third on the Cowboys with 5.5 sacks in 2018. He is as dependable as they come, but he has not had more than 5.5 sacks in a season in his career. Jaylon Smith was fourth on the team in sacks with four. He is a linebacker, and though the Cowboys blitzed more than they had in recent years, that is likely the top end of his sack production.

The eight players under contract for 2019 to record at least half a sack last season combined for 10.5 sacks.

You can see why executive vice president Stephen Jones listed defensive line as the top need from the NFL scouting combine last week.

"In our mind you can never have enough defensive line depth in terms of making sure we've got [enough], especially the way [defensive coordinator Rod Marinelli] likes to play them," Stephen Jones said. "He likes them to play, quote, unquote, with their hair on fire. So I think you can't ever have enough defensive linemen. That's always going to be a situation."

In 2017, the Cowboys used their first-round pick on defensive end Taco Charlton. In two seasons, he has four sacks, including just one in 2018 when he fell out of favor with coaches and was inactive for two games when healthy. He is coming back from offseason shoulder surgery, but Jerry Jones isn't ready to throw Charlton away.

"I never forgot when I got in the NFL, Tom Landry said don't ever complete your judgment on a lineman until his third year. You need that time. You need that experience," Jerry Jones said. "The things that we liked about him [Charlton], I liked about him, what his tool kit is, is enough to be a big-time player for us and get the kinds of snaps that we can get everything we wanted out of a No. 1 pick. He has got that. He tries to incorporate two or three others that he would be better off not doing because that kind of gets him in trouble. From the standpoint of his approach, to getting better as a player, I think it's going to be all uphill from there. I would have liked to have seen him play more last year. But on a personal basis, my perspective, ask me this question at the end of this year. I think I will have a real positive answer for you."

The owner hopes that is the case, just as he hopes for improvement from last year's fourth-round pick, defensive end Dorance Armstrong, but he cannot know for sure.

Just as he cannot know for sure when he will see Lawrence and Gregory on the field again.