Total "QBR" measures all quarterback contributions to scoring accounting for game context and adjusted for opponent strength. It is based on a 0-100 scale, and 50 is average.

ESPN Ranks SEC QBs

6. Zach Mettenberger, LSU (47.0 Total QBR – 80th in FBS)

Mettenberger’s best game of the season came in LSU’s 21-17 loss to Alabama. He posted a 95.5 Total QBR in that game, which was the second-highest Total QBR allowed by Alabama in the Nick Saban Era (Stephen Garcia 97.3 Total QBR in 2010).

Yet, Mettenberger struggled against the rest of the SEC, completing 52 percent of his passes with as many touchdowns as interception (4) in his seven other conference games. He had a below average (below 50) Total QBR in five of those seven games.

5. Jeff Driskel, Florida (59.1 Total QBR – 51st in FBS)

Driskel gained 470 yards and averaged nine yards per rush on designed running plays. As a result, he added the 16th-most clutch weighted expected points on rushing plays in FBS last season.

However, Driskel was sacked 36 times on just 310 dropbacks (11.6 percent). He lost the second-most clutch weighted expected points as a result of sacks, behind only NC State’s Mike Glennon.

4. Connor Shaw, South Carolina (64.6 Total QBR – 38th in FBS)

South Carolina gained a first down on 39.5 percent of Shaw’s pass attempts last season, which ranked seventh in FBS. In addition to precise passing, Shaw scrambled for 225 yards and 13 first downs when the play broke down.

Shaw must improve his downfield accuracy. Six of his seven interceptions last season came on passes of 20 yards or longer downfield. Additionally, he must improve on the road; Shaw’s had an unadjusted Total QBR of 42.8 in five road or neutral site games compared to an unadjusted Total QBR of 77.7 in six home games last season.

3. Aaron Murray, Georgia (78.4 Total QBR – 13th in FBS)

Georgia gained a first down on 40.4 percent of Murray’s pass attempts last season, which ranked third in FBS. Murray led the nation in yards per attempt (10.1) and percentage of pass attempts that gained at least 20 yards (16.1 percent). His Total QBR rank jumped from 21st in his sophomore season to 13th in his junior season.

The biggest question surrounding Murray is his ability to win games against top-ranked competition. In his career, Murray has faced 14 teams that finished the season ranked in the top 25 of the AP Poll. Georgia is 3-11 in those games and Murray had a Total QBR below 60 in seven of those games.

In comparison, Georgia is 25-2 against all other opponents and Murray had a Total QBR below 60 in four of those 27 games.

It is important to note that Total QBR accounts for the strength of the defenses that Murray is facing.

2. AJ McCarron, Alabama (81.1 Total QBR - 6th in FBS)

McCarron posted an above average QBR (above 50) in all 14 of his games last season. McCarron’s worst game was a 53.1 Total QBR against Georgia in the SEC Championship. Every qualified quarterback had at least one worse game (in terms of QBR) during the season. McCarron threw just three interceptions in 314 attempts, resulting in an FBS-leading 10-1 touchdown-to-interception ratio.

Yet two of McCarron’s interceptions occurred inside of his opponents’ five yard line when the score was within seven points. Each of those interceptions decreased Alabama’s win probability by more than 10 percentage points.

1. Johnny Manziel, Texas A&M (90.5 Total QBR – 1st in FBS out of 122 qualified QBs)

Manziel converted a first down on 51.9 percent of his third-down pass attempts last season, best in FBS. He also ran for 28 first downs on third down, including 22 first downs on broken plays. As a result, Manziel led the nation in unadjusted Total QBR on third down (98.6).

In order to repeat his success, Manziel must improve his second-half performance. His unadjusted Total QBR in the first half of games was almost 20 points higher than his unadjusted Total QBR in the second half of games. In Texas A&M’s two losses against LSU and Florida, Manziel had a second-half unadjusted Total QBR of 9.7 and 9.3, respectively.