One of most actively evolving positions for the Indianapolis Colts is defensive tackle. While major trade or free agent acquisitions are atypical for the Colts front office, two of the team's biggest acquisitions in last six years were defensive tackles. In 2005, Indianapolis signed Corey Simon, formerly with the Philadelphia Eagles. Simon's contract was for $30 million over five years. Unfortunately, Simon would never fulfill the terms of the contract on the field as he developed polyarthritis, which forced him into an early retirement. Mid-season 2006, the Colts traded a second round pick to acquire Booger McFarland from the Tampa Bay Buccaneers. McFarland's contract included a $6.6 million salary cap hit. Like Simon before him, McFarland's career would end prematurely -- this time due to a catastrophic knee injury. Since that time, Indianapolis has been attempting to put together a group of defensive tackles primarily through rookie free agency, second round draft picks, late round picks, and by acquiring players from other teams early in the year. When three of those players enter free agency at one time, the likelihood that new acquisitions occur increases significantly. There is a strong likelihood that the Colts will sign one of Antonio Johnson and Daniel Muir. There is a decent likelihood that Indy will re-sign Eric Foster to play the Raheem Brock hybrid defensive lineman role. With only Fili Moala, Drake Nevis, and Ricardo Mathews left as carry-over defensive tackles, the window is certainly open for another upgrade on the defensive interior. The following three free agent tackles deserve consideration from the Colts front office. Brandon Mebane - previous contract 4 years, $2.4 million - 2009 cap hit = $636k Tommie Harris - previous contract 4 years, $40 million - 2009 cap hit = $9.1 million Barry Cofield - previous contract 1 year, $1.76 million - 2009 cap hit = $1.1 million *Approximate cap hit for starting defensive tackles in 2009 $2.5-4.5 million Mebane is the perfect scheme fit for Colts defensive tackles. He is better against the run than most would have predicted entering the league and has the quickness and leverage to penetrate the pocket. At 6-foot 1-inches tall and 311 pounds he is very similar to Indy's rookie tackle Drake Nevis but has proven in Seattle that he is ready to be a solid starter in a 4-3 defense. At 26 years old, Mebane would be an excellent long-term acquisition and could be acquired for a $3.5-4.5 million cap hit. Harris is an intriguing option as a pass rush generating three-technique under tackle. The problem is that Harris's production has been declining over the last three years, he has suffered from nagging injuries, and signing him with expectations of meaningful production will be a risk. On the other hand, there is a high likelihood that the Bears will let him sign with another team and his value has dropped precipitously. If Indy is interested, they could likely bring in Harris for a short-term $3-4 million cap hit. With Fili Moala already on the team, the front office may spend money elsewhere. Cofield is the kind of defensive tackle Indianapolis has lacked for a long time. At 6-foot 4-inches tall and 306 pounds he is a space-eating run stuffer who generated 10 quarterback hits in 2010 -- second to Shaun Rogers. Cofield would be an immediate starter at nose tackle and an instant upgrade. The 27 year old will use his impressive 2010 production to demand a long-term $4-5.5 million cap hit. There are two guaranteed upgrades available in free agency for the Indy front office to ponder. Brandon Mebane and Barry Cofield would significantly improve the Colts run defense and should have a meaningful impact on the pass rush as well. Either player could be acquired without cutting Ryan Diem or Kelvin Hayden's large contracts -- though it would certainly mean that neither Johnson nor Muir would return. If one of the large contracts is unloaded, signing either or both players is possible -- though signing both players is unlikely given Indy's habits in the open market.