Of all of the players on the Colts' 90-man offseason roster, there is perhaps the most uncertainty surrounding right tackle Gosder Cherilus. He struggled through injuries last season and ended up being placed on IR, and the Colts are unsure about his status for this year - it's really a wait and see approach right now, and the status of Cherilus is one that could have an impact on the entire starting offensive line.
Cherilus was signed by the Colts as a big free agent in the 2013 offseason after spending the first five years of his career in Detroit. During his time with the Lions, he played in 75 games and started 71 of them, serving as the Lions' right tackle after finishing his collegiate career at Boston College by starting the final 37 games in a row at the position. The Colts signed him to improve their right tackle position, and in 2013 he did just that. He started every game and played well, and while the offensive line still wasn't great that year, the two tackle spots were fine. Then 2014 happened, however, and it was a disastrous one for Cherilus. It was a season filled with poor play and massive struggles, and a large part of that may have been due to injuries that he fought through. The Colts tried to get him healthy by sitting him for a game but that didn't work out, and right before the playoff run he was placed on season-ending injured reserve. He did end up starting 13 games, but he played very poorly when doing so.
Now, there are questions about Cherilus' health and about how he will come back and play. If he is healthy, he'll likely start at right tackle, and hopefully the issues last year really were because of injuries. But we don't know if he'll come back healthy, and because of that we don't know what the starting offensive line will be. If Cherilus isn't ready, it will likely be Jack Mewhort moving from left guard to right tackle, and it would probably help signify the end of Cherilus' stay with the Colts, as the team would likely keep Mewhort at right tackle and try to groom him there (plus, Cherilus' will have a cap hit of nearly $10 million next season). That would leave a void at left guard, however, and it would likely be either Lance Louis or Hugh Thornton filling in there, though Joe Reitz could factor in as well. The bottom line is that the status of Gosder Cherilus is a big question mark right now, and it's one that could have a significant impact on the starting offensive line for the Colts in 2015.