PHILADELPHIA ( - The mystery surrounding Kiko Alonso's left knee injury continued late Monday as rumors swirled that the inside linebacker could be lost for the season after Philadelphia's 20-10 loss to Dallas on Sunday.

Alonso tore the ACL in the same knee last year, costing him what turned out to be his final season in Buffalo and he struggled with tendinitis at times during the preseason.

The hope things could be less serious comes from the Eagles' reticence to confirm the injury because another torn ACL is a rather simple diagnosis and would have been confirmed by an MRI earlier today.

Two different sources confirmed to that the Eagles fear it could be a season-ending injury, something that would point toward an ACL rather than MCL, PCL or LCL damage. Generally a meniscus injury also wouldn't be fatal to Alonso's 2015 season but with his history, the team could take the conservative approach and shut the Oregon product down.

FOX's Mike Garafolo reported that the there's a possibility Alonso will be lost for the season but that evaluation and conversation is ongoing, which likely indicates Alonso is seeking a second opinion for a partially torn ACL, hoping he could still contribute this season.

Chip Kelly did not address Alonso's status at his press conference earlier Monday.

In other injury news, defensive end Cedric Thornton broke the fourth metacarpal on his right hand, according to freelance reporter Laura Goldman, who took a photo of Thornton  with a cast on his right hand.

On the roster front, the Eagles made a change at the No. 3 quarterback position, swapping out developmental prospect Stephen Morris in favor of veteran Thad Lewis.

Lewis, 27, started five games for Buffalo back in '13 and one for Cleveland a year earlier when Philadelphia offensive coordinator Pat Shurmur was the head coach of the Browns. He spent this preseason back in Cleveland before being released and will offer Kelly some mobility at the position.

In seven career NFL games, Lewis has completed 60.8 percent of his passes for 1,296 yards, five touchdowns and four interceptions.

Morris, meanwhile, is expected to be brought back to the practice squad if he clears waivers.

Also the Eagles made a minor move on the practice squad, signing tight end Chris Pantale and releasing tight end Connor Hamlett.

-John McMullen covers the Eagles and the NFL for You can reach him at or on Twitter @JFMcMullen