Renton, WA -- (Sports Network) - Seahawks linebacker Lofa Tatupu will miss the rest of the season after undergoing surgery to repair his torn pectoral muscle Thursday.

Tatupu visited renowned surgeon Dr. James Andrews on Wednesday in Birmingham, Alabama for a second opinion. Thursday's surgery, performed by Andrews, came after head coach Jim Mora Jr. had raised the possibility of the three-time Pro Bowl selection returning this season.

The initial injury came in a Week 6 setback to the Arizona Cardinals, after which Seattle had its bye week. The fifth-year veteran has 21 tackles and one sack on the year.

Second-year pro David Hawthorne will step into the middle linebacker position and make his second career start on Sunday versus Dallas. Hawthorne started in place of Tatupu in a Week 3 loss to the Bears and recorded and interception and 16 tackles.

In six games this season, the 24-year-old Texas Christian product has 27 tackles and the pick to his credit.