PHILADELPHIA (973espn.com)- The Eagles have signed starting right guard Andrew Gardner to a three-year contract extension which will take him through the 2018 season.

The deal was first reported by ESPN's Adam Caplan.

Gardner won a four-man battle in training camp and through the preseason, outplaying Matt Tobin and recent cuts John Moffitt and Julian Vandervelde to earn the job. By the Eagles ninth practice this summer the Georgia Tech product was inserted with the No. 1s and never surrendered the position from there.

In other news Tuesday, Philadelphia worked out a pair of veteran quarterbacks, Johnson and Thaddeus Lewis.

It's generally standard operating procedure in the NFL to perform your due diligence on certain street free agents that could help in case of injury and the Eagles did that by building a dossier on Johnson and Lewis.

Johnson, a very mobile quarterback with some starting experience in Tampa, was released by the Jets on Saturday and likely could handle Chip Kelly's zone-read looks, while Lewis, who was jettisoned in Cleveland over the weekend, has a five-game stint as a starter in Buffalo back in 2013.

The Eagles currently have Sam Bradford, Mark Sanchez and the recently-acquired Stephen Morris on the 53-man roster but if castastrophe struck the organization and both Bradford and Sanchez went down, the team would likely want a veteran option ahead of Morris, who is more of a developmental player.

-John McMullen covers the Eagles and the NFL for 973espn.com. You can reach him at jmcmullen@phanaticmag.com or on Twitter @JFMcMullen