The Broncos' 2011 draft class was in high demand this month.

Friday, linebacker Nate Irving became the fourth member of that class to join another team in unrestricted free agency when he signed a three-year deal with the Indianapolis Colts.

Irving finally emerged as Denver's first-team middle linebacker in the 2014 season after seeing some starts for Von Miller on the strong side and backup work, and likely projects as the Colts' No. 3 inside linebacker, behind Jerrell Freeman -- a restricted free agent who received a second-round tender -- and veteran D'Qwell Jackson.

But the Broncos' extensive depth at inside linebacker -- which increased when they signed Reggie Walker to a one-year contract Thursday -- left no room for Irving.

Denver re-signed Steven Johnson, who replaced the injured Irving at midseason, to a one-year deal, and had 2014 rookies Todd Davis, Corey Nelson and Lamin Barrow under contract.

Danny Trevathan and Brandon Marshall are currently pegged as the first teamers, and with two players who started in the postseason as backups (Johnson and Davis) Irving would have been in a fight just to make the roster.

In Indianapolis, Irving's spot should be secure, and if someone makes a bid for Freeman on the restricted market, he could start there. Along with re-signed tight end Virgil Green, five Broncos picks from 2011 have signed deals since the start of the new league year. Miller, chosen in the first round in 2011, also had his fifth-year option picked up for 2015, and undrafted signee Chris Harris Jr. signed a five-year, $42.5 million contract in December, further illustrating the quality of the first rookie class under Executive Vice President/General Manager John Elway's watch.