By Scott Garbarini, NFL Editor

(Sports Network) - The Philadelphia Eagles are set to kick off their 2012 preseason, though the atmosphere at Lincoln Financial Field for the team's clash with the Pittsburgh Steelers will certainly have a more somber feel than usual in light of recent events.

Tragedy struck the Eagles family this past weekend when Garrett Reid, the oldest son of head coach Andy Reid, was found dead in his dormitory room Sunday morning at the club's training camp facility at Lehigh University. The elder Reid took a brief leave of absence during the week to deal with the unfortunate situation, but was back at practice on Wednesday and it's believed he'll still be manning the sidelines for Thursday's tilt.

"Knowing Andy, he's a rock," said offensive coordinator Marty Mornhinweg, who had been running practices during Reid's departure. "I would expect him as soon as he gets everything taken care of with his family. This is a tight-knit group that we have and it's clear that what has happened in some ways has made our players even closer."

Though Reid is tentatively expected to be present for the game, to be held two days after Garrett Reid's funeral, Philadelphia will still be fielding somewhat of a short-handed roster against the Steelers. Two starters, left offensive tackle Jason Peters (Achilles tear) and defensive tackle Mike Patterson (brain surgery recovery), are sidelined indefinitely, while All-Pro defensive end Jason Babin (strained calf), tight end Brent Celek (sprained knee) and wide receiver Riley Cooper (broken collarbone) headline the players that will sit out the opener.

Peters' post will be manned by free-agent signee Demetress Bell, while Patterson's unavailability creates an opportunity for 2012 first-round draft choice Fletcher Cox to make a quick impression on a revamped defense that will contain two new starting linebackers in ex-Texan DeMeco Ryans and rookie Mychal Kendricks, a second-round selection in this past draft.

The Steelers are going through a turmoil of a different sort, with big-play wide receiver Mike Wallace currently holding out of camp as he seeks a long- term contract extension. Pittsburgh will also be minus several other prominent players for this matchup, with Pro Bowl outside linebacker James Harrison, running back Rashard Mendenhall, nose tackle Casey Hampton and offensive tackle Max Starks all residing on the physically unable to perform list with knee injuries.

Quarterback Ben Roethlisberger, who's been bothered by a minor rotator cuff tear in his throwing shoulder, is slated to receive some work on Thursday but will likely play sparingly.

With Starks on the mend, rookie second-round pick Mike Adams will start at left tackle on a new-look offensive line that could also contain fellow newcomer David DeCastro on the No. 1 unit by the start of the season. Pittsburgh's first-round pick in this past April's draft, DeCastro is currently operating behind returning regular Ramon Foster as the second-team right guard.

Isaac Redman has locked down the primary running back spot with Mendenhall shelved, but the preseason should bring a spirited battle between third-year pro Jonathan Dwyer and sophomore John Clay to be the main backup.

This will be the 26th lifetime meeting between these Keystone State rivals in the preseason, with the Steelers owning a 15-10 advantage by virtue of three straight wins in the series that includes a 24-14 decision at Heinz Field last season.

The Steelers and Eagles will also face one another in Pittsburgh during Week 5 of this year's regular season.