ESPN NFL draft analyst Mel Kiper Jr. re-graded the 2014 drafts of all 32 teams, and Chicago’s new grade is worse than the B-minus originally handed out in the aftermath of the club’s draft.

Obviously, we all know it takes a few years to truly measure a draft class. But Kiper did put together some parameters in explaining the process. He wrote:

I look at first-year impact from the rookie class based on relative value -- contributing to a winner is worth more than piling up reps for a bad team. I included rookie undrafted free agents added after the draft. (That's part of the process, really. Like the rookie rankings, I try to ask whether players who contributed could do so for most teams. Again, relative value matters.

So Kiper’s draft grades aren’t necessarily based on performance as much as they are based on the total value added based on where he had originally ranked the players.

Kiper liked what the Bears did in aggressively addressing the defensive side of the ball, but pointed out that the club suffered a bit of bad luck in being forced to throw some rookies into the fire, namely cornerback Kyle Fuller, who struggled partly due to experience, but mostly because of nagging injuries.

While defensive tackles Ego Ferguson and Will Sutton flashed at times as rookies, the former appears to possess more long-term upside than the latter. Ferguson and undrafted free agent pickup linebacker Christian Jones each finished 2014 tied for 14th among NFL rookies with two sacks apiece. Ferguson also broke up two passes and Jones notched both of his sacks in the last two games, as he showed growth throughout the season and appears to be set to take on a role at some point as a starter.

A third-round pick, Sutton (25 tackles, no sacks) appeared to be overmatched as a rookie, as did safety Brock Vereen, a fourth-round selection.

The verdict remains out on fourth-round running back Ka’Deem Carey because he didn’t get much action playing behind Matt Forte. Carey averaged 4.4 yards per attempt as a rookie, but didn’t play in the last two games. The expectation moving forward is for Carey to receive more playing time with the Bears moving to more of a run-first philosophy under new coach John Fox.

Sixth-round pick David Fales was active for only one game all season and didn’t play a down. Punter Pat O’Donnell, another sixth-round selection, finished with a 43.8-yard gross punting average, which actually ranked as seventh-best in franchise annals.

Seventh-round pick Charles Leno Jr., meanwhile, played in six games with one start. Still, Leno didn’t see enough action to glean a true evaluation.

Given Chicago’s need at safety headed into the draft, the Bears missed the mark somewhat with the first-round pick. No doubt about it, Fuller will be a long-term fixture at cornerback for the Bears. But current Green Bay Packers safety Ha Ha Clinton-Dix was available with the Bears picked at No. 14 and he’s coming off a rookie season in which he contributed 94 tackles and an interception. In the postseason, Clinton-Dix’s two interceptions in the NFC Championship Game nearly helped the Packers advance to the Super Bowl.