Armstrong made 13 tackles and 0.5 sacks in 2018.
Armstrong didn't suit up for either of the Cowboys' playoff games as a healthy scratch, and he averaged just 18.3 defensive snaps per game in the regular season. The rookie fourth-round pick added depth behind DeMarcus Lawrence and Randy Gregory, both of whom are on expiring contracts.
Armstrong has begun receiving some snaps in practice with the first-team defense, Jon Machota of The Dallas Morning News reports.
A fourth-round pick in this year's draft, Armstrong flashed his pass rushing skills in Thursday's preseason game against the 49ers by recording two QB pressures. The Cowboys' depth chart at DE is suddenly getting crowded with DeMarcus Lawrence, Taco Charlton, Randy Gregory, Tyrone Crawford, Kony Ealy and Armstrong all looking like they could make some contribution in 2018, so the rookie probably won't see enough action to make an IDP splash, but if he continues his development he'll earn a spot in the team's long-term plans.