If a quarterback is ripping up the league in August, does that mean he's more likely to post big numbers in the real games? And if a quarterback is struggling in the preseason, should we avoid him in our fantasy drafts? Ian Allan explores.

It's an issue that was raised by Richard Loppnow last week. And it's a good one. While it's important to make adjustments based on what happens in the preseason games, it's also important not to overreact to what we're seeing. There’s analyzing, and then there’s over-analyzing.

So I've spent the last few hours looking into it. I compiled a database of all preseason quarterbacking numbers of the last four years. Well, not all of them. I tossed out all the lesser guys playing in the second halves. I want just the guys who are either starters or realistically competing for a starting job.

I figured that might help firm up our opinions on the likes of Philip Rivers, Josh Freeman and Eli Manning. Cam Newton, too. Those guys have all struggled in these practice games. How concerned should we be? Does a bad preseason tend to result in a bad regular season?

Well, as exhibit A, let me introduce Michael Vick. He put up the worst quarterbacking numbers of anybody in the last four years, with a passer rating of 38.2 in 2010 (that’s lower than the 39.6 that can be obtained simply by throwing the ball into the ground on every play). That was the same year that Kevin Kolb got hurt in the first game. Vick went on to put up the best quarterbacking numbers of anybody in the last 20 years -- 311 yards per game, with 29 TDs in 11 starts.

Oh, yes. For this deal, in order to reduce the impact of trying to look at guys with varying numbers of starts, I'm looking at per-game numbers. So in the charts below, you see the preseason passer rating, the number of regular-season games he started, his regular-season yards (per game). That's passing plus rushing. And the same for touchdowns. The "rank" is where he finished relative to other quarterbacks that same year in per-game production, using standard fantasy scoring.

Notice that some of the rank numbers have little squiggles. Those are for guys who started less than half the season. For those guys, the number shows where they would rank, relative to guys who started at least 8 games.

So anyway, I'll start with the strugglers (then get the hot quarterbacks later). For guys who in August had passer ratings under 70, which is bad, I see some good ones. Vick in 2010 and 2011. Eli Manning in 2011 and Aaron Rodgers last year. Cam Newton as a rookie. Those guys weren't affected by poor play in August. Their lesser preseason numbers could have been affected by a variety of factors – lack of game-planning, playing with lesser teammates, etc.

For the struggling group, let's set aside the seven rookies, since they're kind of a different animal (trying to adjust to the NFL and whatnot). Of the 18 veterans, 5 went on to have good seasons (top-8 numbers). Three were middle-of-the-pack guys (13th to 16th). And 10 we will call duds (18th or below, with the vast majority in the bottom 10).

So over twice as many misses as hits. So I'm thinking with the way Freeman and Rivers are playing in the preseason, they're not going to be surprise quarterbacks this year.

PRESEASON PASSER RATINGS UNDER 70.0 SINCE 2010
YearQuarterbackRatingStYdsTDRnk
2010Michael Vick38.2113112.641
2012Carson Palmer45.3152701.5316
2011Michael Vick45.9132991.466
2010R-Jimmy Clausen46.810156.3032
2011Alex Smith48.1162081.1925
2013Philip Rivers48.3
2012Kevin Kolb49.792241.0028
2012John Skelton50.672481.14~19
2011Eli Manning51.6163091.887
2012Aaron Rodgers53.8162852.562
2010Brett Favre54.613194.8530
2013R-Geno Smith54.6
2010Matt Moore56.151691.00~31
2013Josh Freeman56.7
2011R-Andy Dalton59.6162221.3121
2012Mark Sanchez59.615194.8730
2012R-Brandon Weeden59.715233.9327
2013Eli Manning60.3
2011Tarvaris Jackson61.9142051.0729
2012Michael Vick62.2102691.3013
2010Jay Cutler62.3152341.6018
2011Kerry Collins62.53160.67~34
2010Kevin Kolb63.752081.20~26
2010Tony Romo64.362741.83~8
2011R-Blaine Gabbert64.314161.8633
2013Cam Newton64.3
2010Matt Ryan64.4162391.7515
2011R-Cam Newton64.9162972.194
2010R-Colt McCoy65.38214.8827
2012R-Ryan Tannehill66.916219.8828

For the guys with the “R” in front of their name, by the way, those are rookies.

Shifting our look to the other end of the spectrum, how excited should we get when a quarterback is slicing and dicing defenses? Sam Bradford has a passer rating of 114.1 -- is he headed for a breakout year?

The results are similar to what we saw with the strugglers. In the last three years (2010-2012), 23 quarterbacks have had passer ratings over 100. Of that group, 10 finished the year as top-9 quarterbacks. Lots of great quarterbacks in there. Another four finished in the top 14. So maybe a 14 of 23 success rate, which is only a little better than 50-50.

Three quarterbacks in this group were just medicore, ranking 16th to 18th in per-game production. And a half dozen of them really weren't any good at all.

So in a rough sense, if you chase after great preseason production, there's a 1 in 4 chance it will really bite you in the butt.

Brandon Weeden has looked good at times this August for the Browns, but notice that team has two of the quarterbacks who've sort of gone from first to worst. Jake Delhomme had a big preseason in 2010, and Colt McCoy was looking like a breakout kind of guy two years ago. The Browns, as a lesser franchise, may be a team that’s trying to create confidence and a winning culture by putting more effort into the preseason games.

PRESEASON PASSER RATINGS OVER 100 SINCE 2010
YearQuarterbackRatingStYdsTDRnk
2011Matthew Stafford154.7163202.565
2011Ben Roethlisberger146.6152761.4016
2010Josh Freeman142.7162381.5616
2010Aaron Rodgers141.2152852.132
2011Aaron Rodgers130.1153273.201
2010Tom Brady128.4162462.316
2013Drew Brees128.4
2012Alex Smith123.692071.4424
2013Tony Romo123.3
2012Tony Romo117.1163101.818
2012Matthew Stafford116.9163181.509
2012Sam Bradford116.3162391.3819
2011Philip Rivers114.8162911.758
2013Sam Bradford114.1
2012Matt Schaub113.3162501.3822
2012Matt Ryan112.4163042.066
2012Drew Brees111.7163242.751
2013R-E.J. Manuel112.0
2010Jake Delhomme110.54193.50~31
2012R-Russell Wilson110.3162251.8812
2010Matt Schaub109.3162751.5014
2011Tim Tebow108.3112071.4512
2013Andrew Luck108.3
2013Tom Brady106.0
2011Kyle Orton104.182211.1327
2012R-Robert Griffin III103.3152681.805
2011Mark Sanchez102.9162242.0013
2013Aaron Rodgers102.3
2011Colt McCoy101.7132251.0823
2012Joe Flacco101.6162401.5618
2013Michael Vick101.1

I've got some similar numbers for running backs that I'm finishing up today. I will work them into the Cheat Sheet Update that's published on Monday morning.