RENTON, WA - As the Seahawks kicked off their second week of training camp on Monday, quarterback Sean Mannion was fluently reciting the contents of new offensive coordinator Shane Waldron's playbook. 

He was signed by the team on Saturday.

"He's really smart. Really smart," Seattle coach Pete Carroll echoed to reporters. "[Quarterbacks coach] Austin [Davis] would tell you: he's been here a day and he's already running the offense. He's already called the stuff. I don't know how a guy could do that. Honestly, I don't even know how a guy could do that."

Mannion was selected by the Rams in the third round of the 2015 NFL Draft, two years before Sean McVay, Waldron and company took over in Los Angeles. Despite the eventual change in command, Mannion stayed in L.A. for the remainder of his rookie contract and served as Jared Goff's backup through the 2018 season.

In the Oregon State product's final year with the Rams, Waldron—a tight ends coach in 2017—was promoted to passing game coordinator. As such, he worked directly with Mannion who, as the best backup quarterbacks do, became a student of his and McVay's passing game philosophy. 

Despite some systematic and terminological changes, Mannion's knowledge has carried over to his reunion with Waldron in Seattle. Providing even more context to how Waldron is running things now compared to his time in Los Angeles, tight end Gerald Everett says the differences and similarities are split right down the middle.

"I'll have to say 50-50, honestly," said Everett, who spent the first four years of his career as a member of the Rams. "But, you know, it's a lot of intricacies and a lot of details that you definitely have to be keyed-in on. There's some similarities, but you look around the league, every offense is running something of the same."

Having fallen under Waldron's jurisdiction in his rookie year, Everett is one of the few individuals in Seattle who can speak from experience on the new offensive coordinator. That's what makes Mannion a valuable piece to the team in its preparation for the upcoming season, using his familiarity with Waldron to help introduce and install the play-caller's new concepts and terms. 

The Seahawks got their first look at Mannion last Monday, bringing him in for a workout prior to the start of training camp. Carroll noted the obvious appeal of the quarterback's background with Waldron, but added that he and his staff were impressed with what they saw.

Mannion has spent the last two seasons backing up Kirk Cousins on the Vikings. Over the course of his six-year career, he's thrown for 384 yards, no touchdowns and three interceptions in 13 games—three of which he started. 

Contrary to initial belief, Carroll says Mannion wasn't brought in to compete with Geno Smith. A former second-round selection of the Jets, Smith has signed a one-year contract with the Seahawks in each of the past three offseasons and has developed a strong relationship with incumbent starter Russell Wilson.

"[Signing Mannion] doesn't have anything to do with Geno right now," Carroll clarified. "Geno's doing great. Geno has had one day after another after another after another. He's really in full flow of the whole thing. But we'll see. If we get down where we're needing three [quarterbacks], then the competition's really on and we'll see how that goes with Alex [McGough]."

Mannion's job, for the time being, appears to simply consist of translating Waldron's system.

"With that background," Carroll explained. "I think he's an interesting guy to bring to camp."

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