As recently as last week, the Seattle Seahawks had Russell Wilson at quarterback and no backups. A week later, they have two backup options. Last week, the Seahawks signed Josh Portis, and earlier today, news came out that the Seahawks were going to sign Brady Quinn.
The Seahawks originally signed Portis as an undrafted free agent back in 2011, and he spent all of 2011 on Seattle's active roster. He spent much of 2012 on the practice squad, and was released after Week 12, at which point he hooked up with the CFL. Although Portis is not a long-term option, he provides some similarities to Wilson in terms of mobility and arm strength.
Quinn was signed after Seattle worked him out on Monday, along with Matt Leinart, Tyler Thigpen and Seneca Wallace. Quinn spent 2012 with the Kansas City Chiefs, starting as Matt Cassel's backup and then taking over as starter midway through the season. He finished with 1,141 passing yards, completed 56.9% of his passes and threw two touchdowns and eight interceptions.
This now leaves the 49ers and Seahawks a couple injuries away from the potential of some combination of Scott Tolzien/Colt McCoy and Brady Quinn/Josh Portis. I don't really know what else there is to be said about that scary proposition.