Aldon Smith finished 0.5 sacks behind Jevon Kearse’s rookie record of 14.5 set back in 1999, but Smith’s year was still good enough for Pro Football Weekly-Pro Football Writers Association to call Smith the 2011 Defensive Rookie of the Year.

The voting wasn’t made public, so it’s not certain how close Smith’s win was over Von Miller, who along with Smith was named to PFW/PFWA’s All-Rookie Team at linebacker. In the PFW article that went over the selections there was an interesting quote about Miller, one that might give a clue as to why Smith surpassed Miller in their minds.

Smith had company when it came to outstanding rookie linebacker play. A thumb injury hampered Broncos OLB Von Miller late in the season, but he recorded 11½ sacks in his first 12 games and was a disruptive presence on all three downs for a much-improved defense.

This is a bit of a surprise, at least to me. I figured with Miller looking like the favorite to clean up in the DROY department from the beginning of the season through November — plus the Tebow factor, which meant more people were paying attention to Broncos games — that Smith would have to at least tie Kearse’s record to surpass Miller in most voters’ minds. From what I wrote on the subject on Dec. 8:

Also, Smith needs to go crazy against the Pittsburgh Steelers a week from Monday. He already has a safety this season, so perhaps grabbing his first interception and returning it for a touchdown would be a nice touch.

Smith made his case against the Steelers, and according to PFW, embarrassing the Steelers’ tackles and quarterback may be what pushed Smith over the edge:

Smith had his share of dominant performances, the most notable being his 2½-sack masterpiece on a national stage against the Steelers the night he set the franchise record for most sacks by a rookie. He totaled seven QB hits and two tackles for loss in the Niners’ 20-3 home victory.

It seems like momentum was key in the PFW/PFWA voting. Miller’s thumb injury led to a slower finish after an extremely strong start; Smith took off about a third of the way through the season and appeared to get better every single week.

So, what about that … other DROY award?

The end-of-season awards handed out by the AP are what get remembered above all others. Head to Pro Football Reference and you can easily find every AP Defensive Rookie of the Year winner since 1967, but they don’t list the awards handed out by PFW/PFWA except MVP.

The interesting thing about the PFW/PFWA DROY award — and why Smith’s chances of winning the AP DROY may be higher than most of us figured — is that since PFW/PFWA started naming Defensive Rookies of the Year back in 1969, the two groups have only differed on their choice four times*.

2004
AP: Jonathan Vilma (LB), New York Jets
PFW: Dunta Robinson (CB), Houston Texans

1984
AP: Bill Maas (DL), Kansas City Chiefs
PFW: Tom Flynn (S), Green Bay Packers

1979
AP: Jim Haslett (LB), Buffalo Bills
PFW: Jesse Baker (DE), Houston Oilers

1972
AP: Willie Buchanon (CB), Green Bay Packers
PFW: Sherman White (DE), Cincinnati Bengals

*PFW didn’t have the award in 1985 for whatever reason.

*There were two years where PFW split the award and one year where the AP did the same. In each of those years, one of the co-DROY’s was named as DROY by the other group of voters.

In reality these awards don’t mean anything compared to what’s at stake on Sunday, and we’ll spend the rest of the week focusing on the NFC Championship Game against the New York Giants. But it’s still worth noting that Smith had an incredible rookie season. He was the 7th-overall pick who many fans weren’t familiar with, and he did enough over the course of the year to convince one group of football observers that he was the best rookie defender — even better than Miller.

San Francisco 49ers named Defensive Rookie of the Year by both PFW/PFWA and AP

2007: Patrick Willis
1993: Dana Stubblefield
1970: Bruce Taylor