The Carolina Panthers are placing both starting rookie defensive tackles — Terrell McClain and Sione Fua — on injured reserve, a person familiar with the decisions said on Tuesday.

The person spoke to The Associated Press on the condition of anonymity because moves have not been announced.

Fua and McClain were both third-round draft picks this year and have been starters since week one. However, Fua suffered a significant right hamstring strain prior to Sunday's game against Tampa Bay and didn't play. McClain sprained his left knee during the first half and did not return.

It's unclear at this point if either player will need surgery.

They become the 13th and 14th players to join Carolina's lengthy list of players on injured reserve — seven on each side of the ball. Defense, however, has been hit particularly hard. The Panthers lost starting defensive tackle Ron Edwards in training camp and then linebackers Jon Beason and Thomas Davis the first two weeks of the season.

In addition, they've also added promising young linebacker Thomas Williams for the season in recent weeks.

McClain started all 12 games and had 20 tackles, one sack, four quarterback pressures and one fumble recovery.

McClain was selected 65th overall in this year's draft while Fua was taken later in the third round at No. 97.

Fua, whose primary job at the nose tackle is taking up space in the middle for others to make plays, had 15 tackles with one quarterback pressure.

Overall, coach Ron Rivera has been extremely pleased with the play of both rookies, while acknowledging the Panthers have had to "take some punches like a little brother." Still, Rivera believes the experience they have gained playing as rookies will be huge for the Panthers in coming years.

The injuries leave the Panthers with only two defensive tackles on the roster — Andre Neblett and Frank Kearse. Neblett is a second-year player. Kearse is a rookie.

Both Neblett and Kearse saw significant playing time in Carolina's 38-19 win over Tampa Bay.

The Panthers also had to slide defensive ends Charles Johnson, Greg Hardy and Antwan Applewhite inside to defensive tackle to help out in certain packages against the Bucs.

The Panthers (4-8) host Atlanta (7-5) on Sunday.