NFL preseason 2014: Johnny Manziel, Jadeveon Clowney debut on Saturday

It's the moment that ESPN has been waiting for since the day the NFL draft ended: Johnny Manziel makes his over-hyped and invariably over-analyzed pro debut on Saturday when the Browns kick off their preseason opener against the Lions. Manziel is still the backup for now, but finishing a strong week of practice with a standout preseason performance could loosen Brian Hoyer's hold on the starting gig (and give pundits a boatload of material).

But Johnny isn't the only talking point on Saturday night. The three other scheduled exhibitions have plenty of intrigue: the Giants running back position is on the verge of becoming an open competition, the Packers get to roll out a new-look defense, the Titans are trying to cement their offensive front … and oh yeah, another notable rookie makes his debut for Houston.

Believe it or not, there's more to watch on Cleveland's offense than just the quarterback position. For starters, there's running back Ben Tate, the free agent acquisition expected to help revive a running game that averaged just 86 yards per game last season. Third-round pick Terrance West will also be making his case for carries. When Detroit has the ball, keep an eye on Ryan Broyles, the former Oklahoma star who has fought through three consecutive season-ending injuries and is finally healthy enough to compete for the Lions' No. 3 receiver spot. Matthew Stafford will also get to try out his other new receiving toy, Golden Tate.

Pittsburgh Steelers vs. New York Giants

Ben Roethlisberger and Todd Haley have apparently buried the hatchet, and we'll have our first look at whether that has any benefit for the Steelers offense. The defense may not get a chance to wheel out first-round pick Ryan Shazier, though -- he's questionable with an ankle injury. The Giants will be without their 2014 first-rounder as well, as wide receiver Odell Beckham Jr. will miss his second preseason game with a hamstring issue. Keep an eye on New York's backfield -- rookie running back Andre Williams was brilliant in the Hall of Fame Game and could be a surprise threat to Rashad Jennings's starting gig.

Green Bay's defense struggled down the stretch last season, but an influx of contributors and some healthy mainstays could have them back on track. Julius Peppers's free agent signing and B.J. Raji's relocation to nose tackle should help out the D-line. Also, Clay Matthews returns to the linebacking corps, and top rookie Ha Ha Clinton-Dix could make an immediate contribution in the secondary. The Titans are hoping Jake Locker can make his long-awaited step forward, and the play of new arrival offensive tackles Michael Oher (free agency) and Taylor Lewan (first-round pick) will go a long way in determining that.

Houston Texans vs. Arizona Cardinals

We finally get to see just how terrifying a defensive front with J.J. Watt and Jadeveon Clowney looks like. That should be a good test for the Cardinals offensive line, which bulked up with the free agent addition of Jared Veldheer. Houston's brand new coaching staff makes their debut, with Bill O'Brian holding the reigns and Romeo Crennel running the defense. The question is, does Houston have a quarterback? Texans fans better hope Ryan Fitzpatrick shows some promise, because there's not much behind him.