The Indianapolis Colts currently have two open spots on their 53-man roster, and they also only have one healthy quarterback in Matt Hasselbeck. If you do the math, it is certain that the Colts will fill one of those spots with a quarterback, adding a backup for Hasselbeck while Luck recovers from a lacerated kidney and torn abdominal muscle that is expected to sideline him for several weeks.
According to Pro Football Talk, the Colts are indeed trying to sign a quarterback. More specifically, they are trying to lure Jason Campbell out of retirement.
Per source, Colts are trying to lure QB Jason Campbell to unretire. He played for Browns the year Rob Chudzinski was the team's head coach.— ProFootballTalk (@ProFootballTalk) November 11, 2015
Campell was drafted in the first round of the 2005 NFL Draft by the Washington Redskins out of Auburn, and Campbell spent five seasons with the Redskins - including starting all 16 games in 2008 and 2009. He then spent two years with the Oakland Raiders (2010-2011), one year with the Chicago Bears (2012), one year with the Cleveland Browns (2013), and one year with the Cincinnati Bengals (2014). He then planned to retire quietly this past offseason.
In his ten-year career, Campbell played in 90 games (starting 79) and completed 1,519 of 2,518 passes (60.3%) for 16,771 yards (6.7 yards per attempt), 87 touchdowns, and 60 interceptions for a passer rating of 81.7. He also rushed for 1,204 yards and six touchdowns while averaging five yards per carry.
As PFT notes, Campbell played for the Browns in 2013 under head coach Rob Chudzinski, and Campbell started eight games that year (playing in nine). Because of Chud's familiarity with Campbell and because of Campbell's experience in the NFL, it makes sense that the Colts would be interested in him. He's familiar with Chudzinski's offense and therefore could help the transition to Chud as the Colts' offensive coordinator.
Of course, it remains to be seen whether Jason Campbell is willing to come out of retirement to back up Matt Hasselbeck for the next month-plus, but according to this report from Pro Football Talk, that's who the Colts are currently targeting. They're surely going to add a quarterback, so it might be another veteran signed out of retirement after an injury to the starting quarterback. What could go wrong with that? Another option the Colts could consider is Charlie Whitehurst, who was just released by the Titans today. Ultimately, however, while the Colts absolutely need depth behind Hasselbeck, if he goes down, they are in serious, serious trouble. It's already tough enough losing Andrew Luck, but Hasselbeck is the best backup quarterback in the league and is very reliable. So if he's injured, the Colts will need someone to step in, but it probably doesn't matter who they sign to do that - because either way, if Hasselbeck goes down, it won't be good.
UPDATE: According to ESPN's Adam Schefter, four teams have tried to lure Campbell out of retirement this year but none have succeeded. Schefter says it is "highly unlikely" that Campbell will return this year.