For one, it established Marsh as the third outside cornerback entering camp. But more important, it signaled that defensive coordinator Juan Castillo intends to use Asomugha much as he did last year - as a roving defender.
"I think a lot of the time I'll be outside," Asomugha said Thursday. "But there are times we can have another guy outside and try to take advantage of other things on the inside. I think Juan is totally comfortable doing that, fine doing that. It's gotten better through the offseason."
When Asomugha arrived last July amid a flurry of change, Castillo said that he wanted to use the all-pro cornerback as Charles Woodson had often been used in Oakland and in Green Bay - which was everywhere and in every which way.
Asomugha played man-press on the outside - his area of expertise in Oakland. He played off corner. He played in various zones. He played in the slot as the nickel. He lined up in the slot over tight ends. He was the dime corner. He even jumped back to safety.
Sometimes it worked, like when he covered tight ends. (Dallas' Jason Witten managed only eight catches for 52 yards in two games with Asomugha mostly covering him.) But many times it did not.
So when the Eagles traded Asante Samuel to the Falcons just before the draft, the move was interpreted - in some circles - as one that would allow Asomugha to return to his comfort zone, which was playing man-to-man press defense.
Asomugha said in May that there probably would be more of that. Rodgers-Cromartie likes to press, as does Marsh. But Asomugha - and Castillo, for that matter - never ruled out having him play multiple spots depending upon the matchup.
"If we're playing a team that we're going to need some matchup stuff, then maybe [Joselio Hanson] is not the guy that's going to be inside," Asomugha said. "Maybe I am, or maybe [Brandon] Boykin is, or maybe I'm going to play the dime again."
Asomugha, it should be noted, said that it will be hard for Boykin or any other competitor to beat out the veteran Hanson for the nickel corner spot. He also said that he thinks the nickel defense will mostly employ a traditional corner like Hanson in the slot.
But having a corner like Marsh, who can play at the line, gives Castillo the luxury to move Asomugha inside if there's a matchup he likes.
"The fact that he's bigger helps out a lot, especially when you want to be aggressive and press," Asomugha said of the 6-foot-1 Marsh. "You would like for the corner to be a bigger guy, a guy that can handle that."
Marsh, drafted in the third round last April, had what many considered a strong camp a year ago. But with three Pro Bowl corners ahead of him, he got on the field for only 13 defensive plays as a rookie.
"He's one of those guys that's really hungry and just waiting for his chance," Asomugha said.
He got his first chance Thursday.
"It felt good just to be out there with those guys," Marsh said. "You play up because you got some of the best in the league looking at you, relying on you, trusting you."
The Eagles will likely throw Marsh into the fire at camp to see if he's ready. His readiness will influence whether Castillo has the flexibility to move his centerpiece around. It's early, and much can change, but Asomugha has consistently said that he's open to playing anywhere.
"I call him the 'Old Head,' " Rodgers-Cromartie said of Asomugha. "He ain't going to say too much, you're not going to get too much out of him, but he's going to do what's required of him."