Bethea is one of the best safeties in the league right now. He's not on Ed Reed's level, but he's amazingly consistent. He's four tackles shy of having a career average of 100 per season and he's only missed five games his entire career. On a team that Bob Sanders robbed of both cap space and a roster spot for YEARS, that's got damn solid. He's spent his entire career chasing RBs that should have been tackled 7 yards earlier because Bill Polian couldn't draft interior defensive linemen or linebackers if his life depended on it. Pat Angerer is pretty solid at LB though, think he finished top 3 in the entire NFL in tackles last season. There are some bright spots on this team. I think Tom Zbikowski taking the starting SS position from Bob Sanders's ghost (who might as well have been playing SS for the Colts since 2009) is a net plus. It's going to be the corners who kill this team. I don't trust a single one of them in a big game moment right now. I don't know what the free agent market for corners is going to be next season, but the Colts are going to have a lot of cap space when the dead cap money from Manning's deal and all the other guys they cut comes off the books at the end of the year. If Andrew Luck has a promising rookie season I can see marquee defensive free agents getting the works from Indy.
Basically I see the Colts at 6-10 like I said earlier. I'd say five of those are on the defense, three on Luck and two on just running into an elite team (GB, NWE). Although the Pats game they'll probably have a chance in just because the Pats like to choke against lesser compe ion and it's still a rivalry game. Those be the hardest to predict sometimes.