Well, looking behind the numbers, his 2 highest looks games were against MIN and PHI. Against MIN Detroit aired it out almost exclusively and against PHI they played a lot of catchup. Recently however the Lions have been trying to shake the one dimentional offense tag and have dedicated themselves to running the ball much more.
They also have had the luxury of having 3-4 (depending on injury) very good WR options this yr as opposed to years past where Roy was clearly the primary. I think the WRs can put up very good stats with 2 primary WRs like last yr (RW and Furrey), but when you add 2 more (McDonald ad CJ) the stats cant help but be deluded somewhat. As a side note, last week was the first time Calvin Johnson started for the Lions - did anyone see the TD run he had? He looked like he was stiffarming his little brother when Cato June tried to bring him down! Megatron is a beast! http://www.mlive.com/lions/index.ssf/20 ... d_run.html
Also, Detroit has actually been able to either lead or keep the score close in about 2/3rds of their games so far this yr so they havent had to play as much catchup as they did last yr. With the renewed dedication to the run along with KJones return, I dont expect them to go back to airing it out like they did to begin the season very often.
All of these things point to Roy Williams regressing from the totals he put up last yr. It obviously doesnt mean he is any less of a player or threat, just that the Lions dont need him as much as they did in the past.