Nearly every team, every year, improves in the offseason. Regardless of player attrition, teams are adding prospects via the draft, although we won't know how much value they'll provide at the NFL level until they take the field. That said, every team has needs to address and there are finite resources on the free-agent market and in the draft with which to address them. So while it may be hard for a team to "fail" the offseason (which is why you won't find any F's below) there are definitely teams that did a better job than others at filling their needs and adding to the talent on their roster.
The teams I graded with an A were the best at addressing their needs and adding talent for 2013 and beyond. Teams with a B did a good job, but there were still a few areas I thought they could have improved. Teams with a C I see as treading water. At best they replaced the talent they lost to free agency and retirement. Teams below a C, well, I think they went in the wrong direction this summer. But there weren't too many.
Here are my 2013 NFL offseason grades for the AFC:
Key additions: OLB Elvis Dumervil, S Michael Huff, DE Chris Canty, DE Marcus Spears, C A.Q. Shipley
Key losses: OLB Paul Kruger, WR Anquan Boldin, C Matt Birk, ILB Dannell Ellerbe, S Ed Reed, ILB Ray Lewis, CB Cary Williams, S Bernard Pollard, G Bobbie Williams, NT Ma'ake Kemoeatu
Analysis: The Super Bowl champions are going to be much better this upcoming season -- on defense that is. Replacing Reed and Pollard with Huff and Matt Elam not only makes the Ravens younger at safety, but represents an upgrade in coverage, versatility and range. Losing Cary Williams hurts a little -- he logged a lot of playing time, but was often picked on -- but the return of Lardarius Webb will make Williams an afterthought.
On this defense, Arthur Brown is most likely to be my choice as NFL Defensive Rookie of the Year. I also think Dumervil is a superior pass-rusher to Kruger. A healthier Terrell Suggs will play every down while Dumervil should rotate with Courtney Upshaw, who plays the run much better than Dumervil but hasn't developed as a pass-rusher. This should maximize Dumervil's snaps. Spears and Canty are defensive linemen who can do a lot of things well, and Canty's interior pass-rushing prowess will be an especially welcome addition.
While I think the offensive line should be quite good if Bryant McKinnie stays motivated, the wide receiver position looks like a gaping hole in Baltimore's offense. Losing the leadership of players like Lewis, Reed and Birk can't be quantified, but this roster has improved overall in their absence. Ozzie Newsome & Co. once again have done a terrific job.
Key additions: QB Alex Smith, DE Mike DeVito, CB Sean Smith, TE Anthony Fasano, CB Dunta Robinson, G Geoff Schwartz, QB Chase Daniel, WR Donnie Avery, FB Anthony Sherman, LB Zac Diles, DL Marcus Dixon, LB Akeem Jordan, DE Daniel Muir, OLB Frank Zombo
Key losses: OT Eric Winston, DE Glenn Dorsey, QB Matt Cassel, CB Javier Arenas, TE Kevin Boss, DE Ropati Pitoitua, WR Steve Breaston, S Travis Daniels, S Abram Elam, RB Peyton Hillis, DL Shaun Smith, G Ryan Lilja, ILB Brandon Siler, QB Brady Quinn
Analysis: This is a much better football team than the one we saw struggle through the 2012 season in very disappointing fashion. There isn't one position on this team that I would say was better in 2012 than it is right now, although we must realize just how badly this team underachieved last season. In fact, the Chiefs look to be noticeably improved at quarterback, tight end, offensive line and defensive back.