Steelers sign first-round pick David DeCastro

Pittsburgh got DeCastro locked down on Monday. (US Presswire)

A league source tells CBSSports.com's Jason La Canfora that the Steelers reached an agreement to sign first-round pick David DeCastro.

Chosen with the 18th overall pick in the 2012 NFL Draft, DeCastro is a physical, mauling guard who should have an immediate impact on the Steelers offense. (I ranked him my third-biggest impact rookie this offseason.)

DeCastro is the second offensive lineman chosen in the first round to reach a deal on Monday -- the Lions and Riley Reiff came to terms earlier in the day.

The Steelers have now finalized signings for every single member of their 2012 draft class.

The Stanford product was the first piece in Pittsburgh's effort to rebuild (or, if you prefer, build for the first time) their offensive line during the draft. The Steelers also drafted Ohio State's Mike Adams in the second round.

For more NFL news, rumors and analysis, follow @EyeOnNFL on Twitter, subscribe to our RSS Feed and subscribe to our Pick-6 Podcast and NFL newsletter. You can follow Will Brinson on Twitter here: @willbrinson.