Circumstances, fortunate or not, and the exceeding of expectations are what can make the NFL preseason great, and in the case of the Dallas Cowboys it’s led to the emergence of rookie quarterback and fourth-round pick Dak Prescott lighting up opponents over two exhibition games this month.

Prescott’s case to serve as Tony Romo’s back-up may already be closed, which could afford head coach Jason Garrett an extra roster spot to reinforce a defense many believe will be sorely lacking in 2016 or provide some extra depth on offense so Dallas isn’t one injury away from ranking No. 31 in points scored for a second straight season.

For Prescott the circumstance was originally projected back-up Kellen Moore breaking his fibula during training camp earlier this month, and the 23-year-old Prescott quickly took advantage of the extra practice reps and preseason snaps to make the league wonder why he fell so low in the draft.

The former Mississippi State superstar’s statistics have likely secured his place on the Cowboys depth chart over third-stringer Jameill Showers with Moore likely done for the season. Prescott, who Dallas selected with the No. 135 overall pick this spring, decimated Los Angeles and Miami by going 22-for-27 for 338 yards and four touchdowns, and gained 41 rushing yards and two touchdowns (both in Week 2 of the preseason against Miami) over five attempts. It’s now possible Dallas won’t have to carry three quarterbacks on the roster, freeing up a spot for any number of veterans or rookies.

Prescott admitted to the Dallas Morning-News he knows defenses aren’t nearly as tough in the preseason compared to a full-fledged game with real implications, but the fact hasn’t hindered his goal or motivation.

"That's on them if they want to throw vanilla or rocky road or whatever they want to throw at me," he said. "It really has no [bearing] on what I do. I just go out there and try to concentrate on our game plan and play my best."

dak prescott cowboys 2016 Rookie Cowboys quarterback Dak Prescott has likely locked up his place as Dallas' back-up and maybe created an extra roster spot for another hopeful first-year player. Photo: Getty Images

A driven rookie who feels confident stepping in immediately could serve as Dallas’ saving grace if Romo goes down again this year. The 36-year-old All-Pro missed 12 games last year and Dallas went 1-11 between Matt Cassel, Brandon Weeden, and Moore in his stead. The Cowboys would finish last season No. 27 in passing yards, No. 22 in total offense, and No. 31 in total turnovers.

But quarterback isn’t the only position in need of depth and like every other NFL team Dallas isn’t immune to the injury bug. Receiver Dez Bryant sat out seven games due to injury in 2015, severely exposing the Cowboys lack of a true No. 2 wide out capable of handling a heavier workload.

Including Bryant and Romo, the Cowboys injury woes were all over the field last season. According to Pro-Football-Reference.com, starters on both offense and defense missed 35 total games either due to injury or suspension, which ultimately led to the Cowboys’ failure to capitalize on 2014’s 12-4 record that included an NFC East title and the first playoff victory in five years.

In the case of Bryant, Dallas may need the extra spot that Prescott affords it sooner rather than later. The three-time, 1,000-yard receiver suffered a concussion during practice Monday and has already been ruled out for Thursday’s Week 3 preseason at the Seattle Seahawks. All told, Dallas has five players listed on injured reserve, including suspended defensive end Demarcus Lawrence.

Due to his determination and excellent performances, Prescott’s likely curried some favor with most of Dallas’ rookies. Each is likely garnering extra attention from position coaches who wonder if they too have a diamond among their rough.

Currently, Dallas is carrying 24 rookies on its roster, and while most won’t make it past the final 53-man cut at least one has a better shot because of Prescott. With Terrance Williams and Cole Beasley likely to keep their places on the roster, rookie receivers Andy Jones and Richard Mullaney could see extra targets against Seattle if Garrett thinks he needs more insurance behind Bryant.

The same could also be said at tight end, the offensive line, or at defensive tackle and end. Former Wisconsin tight end Austin Traylor has just one catch for eight yards, but that could change as Dallas looks for Jason Witten’s eventual replacement. There’s also fourth-round defensive end Charles Tapper, out of Oklahoma, who continues to battle undrafted free agents Rodney Coe and Zach Wood, with third-rounder Maliek Collins behind all of them on the depth chart.