The Cowboys are among 13 teams that changed defensive coordinators. This is the fourth in four seasons for Dallas — Dan Via @WerderEdNFL on X

What happened: Dan Quinn, Mike Zimmer and Matt Eberflus preceded Parker in that order, per Ed Werder.

Why it matters: The turnover puts continuity at issue for the Cowboys: each coordinator transition requires players to adjust to new leadership.

What to watch: Sunday night's opener will provide the first regular-season test of Parker's defense.

Sources