There's little doubting Bironas had a very good year in 2010. He made all of his extra points (for the fifth consecutive season) and a career high 92% of his field goals (24-26). He had a particularly good year from distance, making 10 of his 11 attempts from 40 yards and beyond. In our special teams numbers at Football Outsiders, which take into account distance, weather, and stadium, the Titans ranked second in FG/XP points, narrowly behind the Texans.
Chances are good, though, Bironas won't be quite as valuable a kicker in 2011. Simply put, kickers tend to be inconsistent from year to year. If Bironas attempts the same mix of field goals again, and makes them at his career-average rate, he'd make two fewer field goals than he did last year. If he's as "unlucky" in straight percentage terms as he was "lucky" in 2010, he'd make four fewer field goals than he did in 2010. That alone would probably be enough to push him from among the league's best to average or below, all without changing Bironas's essential quality as a kicker.
The Titans really have been extraordinarily fortunate to have Rob Bironas. 2010 was his luckiest season, but it was actually his second consecutive second place ranking in the FO FG/XP ratings. In terms of raw points, he actually was down from 2009 when he attempted 18 kicks from 40 or more yards out instead of 11 in 2010 (his career average performance from that distance is above-average for all kickers). He also ranked fourth in 2008 and first in 2007, both of which were slightly lucky performances, after a below-average performances his first couple seasons.
The thing to pay more attention will be his kickoff distance. It was excellent, up near 67, in 2007 and 2008, dipped near 64 in 2009, and went back up to 66.5 last year. So long as his leg strength remains an asset, he'll be a good kicker, even if his field goal kicking in 2011 is only of average luck or even unlucky.
*-If it helps, instead of luck, thnk "performance relative to baseline expectations." To determine baseline expectations, I used attempts by distance-20-29, 30-39, 40-49, and 50+. Accuracy rates tend to fall off after 40-42 yards out. Bironas attempted a relatively large number of kicks from 40+ in 2008 and 2009 (38 of 65) but a more modest percentage in 2007 and 2010 (15 of 39 and 11 of 26).