But the eyeball test yielded a few answers after the second-year safety played his first significant amount of football since he ruptured the patellar tendon in his right knee in December. Allen looked a half-step slow and tentative.
The cause, of course, could be the knee. Allen said afterward that his knee "felt good," although a second question provided more detail: "Just sore half of the time, but that's normal," he said.
A less-obvious reason could be the scheme. Last season as a rookie, Allen primarily was responsible for playing center field and serving as the "pass cover" safety, while Quintin Mikell played more in the box to help fill gaps against the run.
The safety jobs were interchangeable, but are even more so this season. Defensive coordinator Juan Castillo even switched Allen's job title. He's the strong safety, and Mikell's replacement - Kurt Coleman - is the free safety.
The title swap means little, but both safety jobs have been tinkered with because new defensive line coach Jim Washburn is lining up the defensive ends farther outside the tackles.
The "wide-nines" scheme, while giving the ends more freedom to rush the passer, takes away some of their run-stopping responsibilities and widens the run gaps along the front. The linebackers are asked to pick up the slack, but so are the safeties.
"There's just a little more responsibility on the runs, especially in certain coverages that we have," Coleman said. "We have to be able to fill these gaps a lot quicker than normally. That's about as vague as I can be."
Last week, when the Baltimore Ravens ran on first down, Allen and Coleman pressed while cornerbacks Asante Samuel and Nnamdi Asomugha took turns dropping back as the safety. Thursday night, the safeties spent more time in the box, but the Steelers still gained 93 first-half yards on the ground.
"It is different from last year," Coleman said. "But we've played this game. We know when we have to fill it on the runs and we know when we've got passes."
Roethlisberger, though, had great success with the play-action pass. All told, he completed 8 of 12 passes for 125 yards and two touchdowns.
The first score - a 29-yard pass from Roethlisberger to wide receiver Antonio Brown - came on third down during the game's opening drive. The Eagles blitzed two extra rushers with Allen coming in off the edge. Inexplicably, he let up and tried to jump and bat Roethlisberger's throw rather than get in the quarterback's face.
Samuel was left alone, gambled on a pump, and Brown was wide open for the touchdown.
Allen also was involved in Pittsburgh's second score in the second quarter. Again on third down, Roethlisberger connected with another of his receivers, Hines Ward, for a 20-yard touchdown.
This time, Allen dropped back into coverage.
"When Roethlisberger scrambled, Ward kind of broke his route off," Allen said. "That's when you've got to hug up on somebody, and he just got behind me."
A preseason loss in no way compares to a defeat in the regular season. Last season, Allen dealt with a brutal experience when Tennessee's Kenny Britt torched the Eagles defense - particularly Allen and cornerback Ellis Hobbs - for 225 receiving yards.
Allen rebounded from that performance and, overall, had a fine rookie season. But with Mikell at his side, he wasn't asked to shoulder as much. Now his role in the defense has changed, and he is being asked to assume some of Mikell's duties.
"Q - obviously it hurts to lose a guy like that," Allen said. "That's how it is, and you've just got to step up and everybody else has got to step up."
A healthy knee would make it easier.
Contact staff writer Jeff McLane at 215-854-4745, firstname.lastname@example.org, or @Jeff_McLane on Twitter.