In no way is the preseason opener against Pittsburgh a limited-viewing option. Everything is in play and everyone is under the microscope. We've seen the Eagles on the field since the spring and all the way through this Training Camp, and yet everything changes once the games begin. For a list of seven Eagles – a list that could be so much longer, let's be honest – the preseason opener represents a new beginning. For the coaching staff and the personnel department, the game against the Steelers is a period of discovery.

None of the players below is a rookie. Each has a story. But the new Eagles chapter starts in the opener, and with that, a great chance to evaluate their chances of making the 53-man roster and having an impact in 2018.

Here are seven players to watch against Pittsburgh:

LaRoy Reynolds, LB

In his sixth NFL season, LaRoy Reynolds has played with Jacksonville, Chicago, Jacksonville again, and Atlanta. He's played in 68 career games. Reynolds is a known commodity in the league as physical, versatile linebacker who makes a positive difference on special teams. The Eagles signed Reynolds in May as an unrestricted free agent and expect him to add depth at linebacker and play on special teams. Linebacker has been an interesting group to watch in camp, although it's really an incomplete picture at this point. The preseason games are going to say a lot about the starting job on the weak side – Nathan Gerry, Kamu Grugier-Hill, and Corey Nelson are the leading contenders – and depth throughout all three positions. Reynolds could very well play a key role here, especially with Nigel Bradham serving a one-game suspension to open the season.

Joshua Perkins, TE

The Eagles seem set at tight end with Zach Ertz, Richard Rodgers, and rookie Dallas Goedert all lined up to play together. That is a very promising trio. But with Rodgers sidelined lately, Joshua Perkins has been able to get some playing time and has caught quite a few passes. He'll get some playing time against Pittsburgh. Perkins played with Atlanta in 2016 and caught three passes for 42 yards. Let's see how he fares in the preseason opener. At the very least, Perkins is creating excellent competition at tight end for the Eagles.

Sidney Jones, CB

One of the summer's most-anticipated stories is how second-year man Sidney Jones develops in his first on-field summer with the Eagles. Jones didn't play in last year's preseason, as he used the time to recover from his pre-draft Achilles tendon injury. Jones played in the regular-season finale against Dallas and used his offseason to get bigger, faster, and stronger. So far, we've seen Jones line up primarily as the team's nickel cornerback, along with De'Vante Bausby and Avonte Maddox, so this test on Thursday night will be significant. Where is Jones in his development? We're going to learn a lot in the preseason, starting in the opener.

Nate Sudfeld, QB

The Eagles want to learn about Nate Sudfeld, and they're going to have that chance in the preseason. He's a big, strong third-year quarterback who has come a long way since the Eagles added him to the practice squad last September. The value of good coaching and a player's work ethic cannot be overstated. The Eagles think Sudfeld can develop into a starting-caliber quarterback in the NFL. He's going to have an opportunity in the preseason to show what he can do.

Donnel Pumphrey, RB

This preseason is the moment of truth for Donnel Pumphrey, a fourth-round draft pick in 2017. Can he show the elusiveness the Eagles saw from his days at San Diego State? Does Pumphrey have the burst to win through the hole in the running game? Pumphrey lacked juice in last year's preseason, and now he faces an extremely competitive battle for a roster spot in a crowded running back room. He'll get touches, for sure. Pumphrey has to make something happen to win a spot on this roster.

Isaac Seumalo, C

After an encouraging rookie season in 2016, Isaac Seumalo entered the 2017 preseason as the team's starting left guard. He took a step back, though, and relinquished the position to Stefen Wisniewski early in the regular season. Now Seumalo is playing the center position, perhaps his most natural spot. Seumalo isn't going to unseat first-team All-Pro Jason Kelce, but he has a chance to show that he can be relied upon at the position. Seumalo has played tackle and guard and if he can also play center, he can be an incredibly valuable piece across the board along the offensive line.

Shelton Gibson, WR

A rough rookie summer for Shelton Gibson is a thing of the past. Gibson was having a very fine Training Camp for the Eagles until he suffered a concussion last week. After missing several days of practice, Gibson is back on the field and looking to pick up where he left off. A roster spot is there for Gibson, who faces some very real competition from veterans like Markus Wheaton and Kamar Aiken. Gibson has the wheels to make it here and be a deep threat in the passing game, but he's got to catch the football consistently.

The preseason is here! The Eagles have some legitimate competition across the board. And while you can think what you want of the viability of the preseason, understand how important it is for the players, some of whom we're going to learn a whole lot about on Thursday night.