Another key defensive player went down for the Green Bay Packers as starting nose tackle B.J. Raji suffered a concussion during Sunday's 38–8 defeat to the Arizona Cardinals on the road.

According to ESPN, Raji sustained the injury in the last play of the first quarter which forced him to leave the game and head to the locker room.

Once he was in the locker room, the 29-year-old nose tackle was diagnosed with concussion and never returned to the game.

In 14 games played this 2015 season, his first year back after missing the entire 2014 season due to a bicep injury, Raji has 21 tackles.

Raji's injury is a tough blow for the Packers especially if he will be missing games since the nose tackle position is very important for the team's 3–4 defensive scheme, according to Bleacher Report.

Bleacher Report also mentioned in its report that the number two nose tackle on the Packers' depth chart is Mike Pennel, who "lacks experience," but will likely see action if Raji is sidelined.

Raji joins cornerback Sam Shields, who is also an important player on defense for Green Bay, but missed the last two games because of concussion as well. 

The Packers will now wait for Raji as he goes through the National Football League's (NFL) concussion protocol program and may return to action once he gets cleared.

Green Bay's recent defeat to the Cardinals ended a three-game winning streak and tied it with the Minnesota Vikings for the top spot in the National Football Conference (NFC) North with a 10–5 record.

However, the loss did not affect the Packers, who, along with the Kansas City Chiefs, Vikings, and the Seattle Seahawks, have already clinched a playoff berth for the 2015 season.

The last regular season game for the Packers will be a showdown between them and the Vikings on Jan. 3, 2016, with the winners taking the top spot in the NFC North as the regular season closes.