Indianapolis Colts linebacker Darius Leonard has been ruled out of his team's Week 3 matchup against the Atlanta Falcons on Sunday due to a concussion, according to Stephen Holder of The Athletic.

This is a significant blow to a Colts defense that will face a high-powered Falcons offense this weekend.

Through two games this season, Leonard has logged 18 tackles and a sack.

Leonard, who played his collegiate football at South Carolina State, was originally selected by Indianapolis in the second round (36th pick overall) of the 2018 NFL Draft.

Little did the Colts know they would be drafting an instant star.

The 24-year-old shined in his rookie campaign, leading the league with 163 tackles while also racking up seven sacks, a couple of interceptions, four forced fumbles, a pair of fumble recoveries and eight passes defended.

Somehow, Leonard did not make the Pro Bowl, but he did earn a First-Team All-Pro selection.

Indianapolis' defense has only been so-so out of the gate, as it currently ranks 14th in the league in yards allowed and 22nd in points allowed. Without Leonard, the task of defending Atlanta becomes that much more daunting for Indy.

The Colts have gone 1-1 over their first two games, losing to the Los Angeles Chargers in overtime in Week 1 before topping the Tennessee Titans this past weekend.

This game will represent Indianapolis' home opener.

Indy was dealt a devastating blow a couple of weeks before the season began, as franchise quarterback Andrew Luck announced his sudden retirement, but thus far, Jacoby Brissett has filled in admirably.