Did you know these 8 NFL quarterbacks could have played professional baseball?

Some folks will tell you that quarterback is the most difficult position to play in all of sports. Those people probably haven't tried to hit Jake Arrieta's breaking ball, but we get what they're saying. 

So, it's hardly surprising that many high quality NFL quarterbacks, at some point in their athletic careers, experienced enough success on the diamond to warrant a selection in the MLB Draft. It should be noted that the inverse is also true, as MLB All-Stars Todd Helton backed up Peyton Manning at Tennessee, Vince Coleman was an all-conference kicker and punter (so was his cousin who had a 12-year NFL career), Jeff Samardzija might have been a first-round pick and Kirk Gibson was an All-American wide receiver. Oh, and then there's Bo Jackson, too.

With NFL action kicking off on Thursday night, it's time to look back at which gridiron stars picked door No. 2, even though door No. 1 would have led to a career in professional baseball.

Tom Brady - Though you might not know it from watching his most recent first pitch effort, four-time Super Bowl champion Tom Brady was once an MLB Draft prospect.

The Expos selected Brady, a catcher, out of Junipero Serra High School in Southern California in the 18th round of the 1995 MLB Draft. Brady turned 'em down to play football at Michigan and never looked back, though his high school coach thought he had potential on the diamond: 

And there is baseball in the family now that Brady's sister is married to former Red Sox infielder Kevin Youkilis. Every Thanksgiving is like a mini summit of New England sports heroes.

Matt Cassel - Fancy that. The guy who's pretty much only famous for having backed up Brady on the Patriots (and Carson Palmer and Matt Leinart at USC) might have had a shot at a career as a starter ... in an MLB rotation. Cassel says that baseball was his first love -- and it's not hard to see why, considering that he played in the 1994 Little League World Series. Cassel hit .429 and played every inning at first base as his team won the West region, but lost the tournament title game.

ICYMI: #Vikings Matt Cassel recalls playing in the Little League World Series in 1994: http://t.co/3hwCaUFUbF pic.twitter.com/G6Sy44X5e5

- KSTP (@KSTP) August 25, 2014

Despite his early success -- and the fact that he had two brothers who'd go on to play pro baseball -- Cassel dropped baseball during his junior year of high school so that he could focus on football. While at USC, Cassell returned to the diamond and, in 2004, went 0-1 with a 9.35 ERA in 8 2/3 innings of work. The Oakland A's drafted him in the 36th round of that year's MLB Draft.

When Cassell was playing for the Chiefs and the MLB All-Star Game rolled into Kansas City, he played left field and third base and earned two base knocks batting in the celebrity softball game (thanks to some serious protection in the lineup in the form of Hall of Famer George Brett.)

Kerry Collins - The Tigers went on a bit of an NFL run in 1990, drafting Collins (as an infielder in the 26th round) and fellow future NFL-ers Greg McGurtry and Rodney Peete. Collins played in state championships for baseball and football, but committed to Penn State with pigskin as a top priority. Though, he did go on-the-record with his intentions to try his hand at college baseball, too. The Tigers drafted him again in '91, and the Blue Jays selected him in '94. Collins went on to enjoy a 16-year NFL career that featured two Pro Bowls, a Super Bowl berth and more passing yards than you probably remember (40,922).

John Elway - Before he was a nine-time Pro Bowler ... before he appeared in five Super Bowls (winning two in a row) ... before he was immortalized in Canton, Ohio: George Steinbrenner's Yankees selected Elway in the second round of the 1981 MLB Draft. Elway played one season for Oneota of the New York-Penn League, hitting .318/.432/.896 with 12 extra-base hits and eight (!!!) outfield assists in 42 games. Elway hit .551 and .491 in his last two years of high school ball and won Los Angeles High School Player of the Year, but he'd been away from the game for more than a full calendar year before suiting up for Oneota.

When the Colts selected Elway with the No. 1 overall pick in the 1983 NFL Draft, Elway held a draft-night press conference to say that he'd play for the Yankees before signing with the Colts. Six days later, Baltimore traded him to the Broncos.

Johnny Manziel - Johnny Football gave up on baseball when he graduated early from high school to prepare for life as a collegiate quarterback at Texas A&M. But after he homered while taking batting practice at Petco Park and threw out as entertaining (and accurate) a first pitch as you could think up, the Padres simply couldn't pass on him.

The team selected Manziel in the 28th round of the 2014 MLB Draft. Manziel fancied himself a middle infielder and even flirted with the idea of playing as an Aggie, but when he won the starting QB job as a redshirt freshman, he decided to focus on football. Manziel is currently listed as the No. 2 quarterback on the Browns roster.

Dan Marino - During his senior season at Central Catholic High School in Pittsburgh, Marino went 23-0 as a RHP, played shortstop and hit better than .500. Back then, he could run the 40 in 4.7 seconds, too. So, it wasn't a huge surprise when the Royals took a flyer on a kid who seemed destined to play football at the University of Pittsburgh. Marino turned the Royals down and went on to be one of the most prolific passers in NFL history, throwing for 420 touchdowns and more than 61,000 yards over 17 years with the Miami Dolphins.

In 2013, Marino -- a lifelong Pirates fan -- appeared at PNC Park and threw a ceremonial first pitch strike to fellow Yinzer Neil Walker:

Ken Stabler - Known as affectionately as "The Snake," the Raiders legend was selected in three MLB Drafts (Yankees in 1966, Mets in 1967 and Astros -- with the 24th overall selection -- in 1968). Stabler, though, opted for a career in football after the Raiders selected the southpaw in the second round of the 1968 NFL Draft. He went on to win the 1974 NFL MVP and lead the Raiders to a victory in Super Bowl XI. Sadly, Stabler, 59, passed away last year.

Russell Wilson - You know Russell Wilson as the Super Bowl XLVIII champion quarterback of the Seattle Seahawks who spends some of his offseason hanging out at Rangers Spring Training. The Orioles selected Wilson as a high schooler in the 2007 MLB Draft, but Wilson decided to pursue a football career (and a college education) at NC State. As he transferred to Wisconsin, the speedy second baseman was again selected in the 2010 MLB Draft, this time by the Rockies. 

Wilson again picked football, but played Class A ball in the Rockies system and posted a .229/.354/.356 line with 19 steals in 93 games. He was later selected in the 2013 Rule 5 Draft by the Rangers and continues to make some appearances at Spring Training.

A number of other notable QBs had a shot at careers in baseball including ...

Archie Manning, Steve Bartkowski, Jay Schroeder, Bubby Brister, Chris Weinke, Rodney Peete, Tony Banks, Rob Johnson, Steve McNair, Mark Brunell, Akili Smith, Quincy Carter, Michael Vick, Brandon Weeden and Colin Kaepernick.