The best thing about preseason football is it's a chance to see the rookies in action against NFL opposition for the first time. It's often against second- and third-stringers, of course, but it's better than nothing. Four of the first-round quarterbacks debuted yesterday, including Chicago's Justin Fields.

The Bears have said Andy Dalton will open as the starter, but teams with a capable veteran in place always say that, and it doesn't always work out that way. The facts are that Aaron Rodgers or Patrick Mahomes sitting on the bench for a year or three seldom happens. First-round quarterbacks tend to play quickly. We know Trevor Lawrence and Zach Wilson will be Week 1 starters, and it's entirely possible that Mac Jones, Trey Lance and Justin Fields will be. Even if not, all will probably see the field sooner rather than later this season.

Fields replaced Dalton after two series yesterday, and it was a pretty positive debut: 14 of 20 for 142 yards and a touchdown. He also ran it 5 times for 33 yards and a touchdown, and that's what makes him especially interesting in fantasy terms. Fields called to mind Lamar Jackson or Michael Vick -- a guy who will be looking to pick up yards with his legs at the first sign of trouble in the pocket. That can be problematic (opponents will try to force him to beat them with his arm), but there's a nice payoff to that kind of game in fantasy leagues.

Over the past 20 years, six rookie quarterbacks have run for at least 500 yards, and five more have run for 350. Nearly half (5) of those dual-threat quarterbacks have used that production to finish in the top 12 at the position in their rookie seasons. Three other quarterbacks who ran for at least 200 yards as rookies ranked in the top 10 at their position. Each of those players also passed for very good numbers (Andrew Luck, Dak Prescott and Justin Herbert) but the running production helped a lot. Top-12 quarterbacks in bold.

TOP RUSHING NUMBERS FROM ROOKIE PASSERS, 2001-PRESENT
YearPlayerGPassTDAttRunTDRk
2012Robert Griffin, Was.15320020120815710
2011Cam Newton, Car.16405121126706143
2018Lamar Jackson, Balt.1612016147695530
2018Josh Allen, Buff.1220741089631822
2006Vince Young, Ten.1521991283552712
2019Kyler Murray, Ariz.163722209354446
2012Russell Wilson, Sea.1631182694489411
2017DeShone Kizer, Cle.1528941177419522
2014Blake Bortles, Jac.1429081156419021
2013Geno Smith, NYJ1630461272366620
2020Jalen Hurts, Phil.151061663354336
2019Gardner Minshew, Jac.1432712167344021
2001Michael Vick, Atl.8785231289134
2016Dak Prescott, Dall.1636672357282610
2002David Carr, Hou.162592959282324
2019Daniel Jones, NYG1330272445279220
2017Deshaun Watson, Hou.716991936269227
2012Andrew Luck, Ind.164374236225559
2015Marcus Mariota, Ten.1228181934252222
2017Mitchell Trubisky, Chi.122193741248229
2020Justin Herbert, LAC154336315523459
2010Tim Tebow, Den.9654543227634
2011Christian Ponder, Min.1118531328219028
2015Jameis Winston, T.B.1640422254213613
2012Ryan Tannehill, Mia.1632941249211224
2014Teddy Bridgewater, Min.1329191447209122

As a starter for Ohio State the last two season, Fields rushed for 867 yards and 15 touchdowns. He might not be that prolific a runner with Chicago, but it will be a big part of his game. Plenty of upside once he pushes Dalton to the sidelines.

--Andy Richardson