If you listen to what the NFL's head of officials has said about read-option quarterbacks, Suggs was simply playing within the rules.
On the Eagles' sixth offensive snap, Bradford handed the ball off to running back Darren Sproles and then immediately sustained a hit from Suggs on his surgically repaired knees. According to NFL rules, Bradford is a runner when he makes the read-option fake and his only protection is normal unnecessary roughness rules (which doesn't include low hits).
In 2013, the NFL released a video to the media clarifying the rules for read-option quarterbacks.
"The key point is that the quarterback does not get special protections at all times throughout the play," said Dean Blandino, NFL's vice president of officiating. "When he is a passer, that's when he gets the special protections whether it's roughing the passer or defenseless player protection. [But on read-option fakes], he is considered a runner at that point. Just like a running back who has the football, defenders can hit him. He is not presenting a passing posture."
As a runner, the quarterback loses the protection of the one-step rule (defenders must stop themselves if they are two steps from a quarterback in the pocket who has released the ball) and the protection against a low hit.
In regards to Suggs, it isn't a foul. QB does not get protection running read-option or zone-read. Might be cheap but not a foul.— Mike Pereira (@MikePereira) August 23, 2015
According to Rule 12, Section 2, Article F, the quarterback is no longer treated as a runner until he "is obviously out of the play." It's difficult to argue that Bradford was out of the play because an unblocked Suggs hit Bradford as soon as he had handed the ball off.
Suggs was doing his job on the play. He was preparing for the read-option because the Eagles had run it twice on that series already. It's not his responsibility to pull up and wait to see if Bradford has the ball or not. And, if Suggs bites on a fake to the running back, that allows Bradford to escape the pocket for a big play by either running with the ball or throwing it.
"When you run the read option, you have to know the rules," Suggs said. "If you want to run the read option with your starting quarterback that's had two knee surgeries, that's on you. That's not my responsibility to update you on the rule."
Whether Suggs had to go low to tackle Bradford is a subjective call. The repeated fines over his career -- like the one for his late hit on Steelers running back LeGarrette Blount last season -- will lead to speculation that Suggs was intentionally trying to hurt Bradford.
The NFL reviews every play of every game for potential discipline, including all preseason games. If the league decides to discipline Suggs, an announcement of a fine would likely come Friday afternoon.
But there doesn't seem to be a case to further punish Suggs for roughing the passer when Bradford was a potential runner.
Information from ESPN NFL Nation's Kevin Seifert was used in this post