The moment Nnamdi Asomugha was released by the Eagles, San Francisco became a widely-rumored destination. Now, rumor has become reality, and he’s signed a one-year deal with the defending NFC champs, according to ESPN’s Adam Schefter.

But while reporting the latest signing with free agency now officially in its third week, The Scheft also passed along a peculiar (see: sort of baffling) contract detail. Asomugha will make a base salary of $1.35 million during the 2013 season that could increase to $3 million with incentives, but he won’t get a dime of guaranteed money. Why? He didn’t want any.

The explanation for that is surely the $4 million in guaranteed money Asomugha will still receive from the Eagles next year. That, and the knowledge that he’d get very little guaranteed cash from San Francisco anyway, and it could have been a deal breaker. Still, a veteran pursuing zero guaranteed dollars in a new contract isn’t a wise practice, regardless of the situation. Asomguha could rip an ACL during offseason workouts, and not see a dime from the Niners.

But hey, good on you then, 49ers. Even though his coverage skills declined abruptly in Philadelphia, Asomugha can still be a valuable asset in a role which doesn’t demand that he lines up against the opposition’s top receiver on every snap. That’s where he now fits in San Francisco’s secondary, with Carlos Rogers capable of sharing spotlight duties. Asomugha’s value increases further with his extremely minimal cost, and especially the guaranteed money that doesn’t exist.

This is the first step towards replacing the overall coverage skills lost in the Niners’ secondary when Dashon Goldson left for the Bucs. It’s a feeble one in that sense, but there’s hope that at the not young but still not old age of 31, Asomugha could regain the form he showed the last time he played on the left coast for Oakland. Next up: a safety in the first round.