Published: Aug 04, 2010 2:44 AM EDT
Updated: Aug 04, 2010 4:31 AM EDT

JACKSONVILLE, Fla. (AP) — Jacksonville Jaguars rookie D'Anthony Smith has an Achilles' tendon injury that will require surgery and could force him to miss the season.

Smith, a 6-foot-2, 298-pound defensive tackle and third-round draft pick from Louisiana Tech, pulled up lame during drills Monday night. Tests on Tuesday revealed the seriousness of the injury.

Jaguars officials say Smith is out indefinitely.

If he does end up on injured reserve, it would be a setback for a team trying to revamp a defense that finished last in the league with a franchise-low 14 sacks last season.

Making matters worse, defensive end Aaron Kampman (knee) has missed consecutive practices and defensive tackle Terrance Knighton continues to battle weight problems.