Per ESPN's Ed Werder, "Brady Quinn was the most impressive of four NFL quarterbacks trying out for the Seattle Seahawks and the team will try to sign him to back up starter Russell Wilson, sources said." USA Today's Mike Garafolo echoed that, noting it "sounds like Seattle will be signing Brady Quinn," and NFL.com's Ian Rapoport is "hearing the same."
UPDATE: Jason La Canfora confirms the Hawks have indeed signed Quinn.
Quinn posted a career-best 56.9% completion percentage in 2012 (112-of-197), passing for 1,141 yards with 2 TD to 8 INT. He's thrown for 53.8% completion rate in his career, with 3,043 yards 12TD to 17INT. Quinn started 8 games for the Chiefs in 2012, with his best performance against Carolina in Week 13 (a big upset win), and the former Notre Dame star and first-round pick threw for 201 yards on 19 of 23 passing, 2 TD and no picks. The rest of his 7 starts, all losses for Kansas City, were not so successful. Bad, actually.
Nonetheless, he's athletic and mobile, which fits the profile for quarterbacks the Seahawks have been interested in over the years. Though it was back in 2007, I guess it's worth noting, so you get an idea of his athleticism, that at his pro day, Quinn ran a 4.73 40, a 6.79 3-cone, a 4.22 short shuttle, had a 36" vert, and a 9'7 broad jump at 6'4, 232 pounds. But, after being chosen #22 overall by the Browns, he's struggled as a pro. Assuming the Hawks and Quinn can work out a deal, he'll compete with Josh Portis and any incoming draft picks for the QB2 spot on the roster. Seattle only kept two quarterbacks on their active 53-man roster in 2012.