Comparing quarterbacks is always tricky.
Is Jameis Winston better than Marcus Mariota?
Are either or both better than Johnny Manziel?
Those questions are fun to debate but impossible to answer. Even with every measurable statistic being calculated and studied like the national security data, the yardages, completions, touchdowns and quarterback ratings don't quantify which offensive lines, receivers, running games or defenses offered their quarterbacks with most breathing room.
It's also difficult to judge the quality of the opponents each quarterback has played against.
Is a one-loss Pac 12 defense better, worse or the same as a two-loss SEC defense, or an undefeated ACC defense?
These are the questions that nourish sports radio shows and internet chat rooms, and fuel fans to cheer of curse their QBs on an almost daily basis.
That brings us to Saturday's showdown between LSU and Alabama, teams that field quarterbacks whose performances in this game could define their college careers.
Should LSU's Zach Mettenberger pull off the upset in Tuscaloosa against one of the top defenses in the land, all his previous missteps would almost certainly be forgotten.
On the flip side, AJ McCarron, owner of two BCS national championship rings, could go down as one of the greatest field generals in college football history if he continues to win games for the Crimson Tide.
Is either the best quarterback in the land? Almost certainly not, but they both have opportunities to boost their national profiles and draft statuses with impressive performances on Saturday.
Mettenberger comes in with 2,492 passing yards and 19 touchdowns, which is slightly better than McCarron (1,864 yards and 13 TDs). But the Tigers have played one more game and have beaten up on UAB, Kent State and Furman — where Mettenberger tallied 11 of his 19 touchdowns.
Of course, McCarron has padded his numbers as well, logging nine touchdowns against Georgia State, Colorado State and bad Kentucky and Arkansas clubs.
Against quality opponents, the numbers begin to even out. Mettenberger threw for 229 yards and one touchdown in a win against Auburn, and had 372 yards and three TDs in a losing effort to Georgia.
McCarron threw for 275 yards and two touchdowns against a much-improved Tennessee team and had an epic game in College Station — completing 20 of 29 passes for 334 yards and four touchdowns against Texas A&M.
Even looking at the only common opponent between the two teams — Ole Miss which Alabama played on Sept. 28 and LSU played on Oct. 19 — the numbers are a mixed bag. McCarron was a serviceable 29 of 32 for 180 yards against the Rebels; while Mettenberger completed 19 of 33 passes for 274 yards and a touchdown.
The big difference: McCarron didn’t need to do much — the Tide rolled over the Rebels, 25-0 — while the Tigers lost their game in Oxford 27-24, largely due to three Mettenberger interceptions.
Both have only played one team with a ranked defense and neither has set the world ablaze. McCarron went 10 for 23 for 100 yards against Virginia Tech in the season opener, tossing one touchdown and one interception.
Mettenberger went 9 for 17 for 152 yards against a top-10 Florida defense. He didn’t throw any touchdowns or interceptions in LSU's home victory.
Based on this, one would have to call the quarterbacks a toss-up this weekend. But there are some numbers that aren't vague or ambiguous, numbers that separate the two and should be looked upon as indicators of what to expect:
As a starter McCarron is 33-2 ... and Mettenberger 17-5.
At the end of the day, wins are all that matter.
