Brent Grimes was rated the second best cornerback last year by Pro Football Focus, behind only Darrelle Revis. Now his season is over, and while the Falcons’ have depth at the position after the signing of Asante Samuel, and while rejoicing over a man’s injury makes us the kind of fantasy douche that Arian Foster hates, the reality of our fantasy is that this is very awful news for Grimes, and very good news for anyone who owns a premier receiver who’s set to line up against the Falcons.

Grimes left Atlanta’s easy win over the Chiefs late in the fourth quarter yesterday, and an MRI revealed that he has a torn ACL which will require season-ending surgery. Now the desired effect of the Samuel trade has been almost immediately nullified after just one game.

During his rehab Grimes will live between two bowling allies.

The Falcons’ intention when they traded to acquire Samuel and then forced Grimes to sign his one-year franchise tender was to do their best impression of the defensive backfield frequently trotted out by Samuel’s former team. When he was in Philadelphia last year, Samuel was frequently on the field alongside two other elite corners in Nnamdi Asomugha and Dominique-Rodgers Cromartie, one of whom was designated the nickel corner (most often Rodgers-Cromartie). This year the names would change, but the end result would ideally stay the same, with Grimes alongside Samuel and Dunta Robinson. The three corners were on the field at the same time for all but 11 of Atlanta’s defensive plays yesterday against Kansas City.

The premise then in Philly and now in Atlanta was the same: in a league where offenses are increasingly using the pass to burn defenses and win games, that firepower can most effectively be fought with an abundance of top flite corners. It’s an emphasis we’re also seeing in Buffalo, where the Bills spent a first-round pick on Stephon Gilmore last April, and a second rounder on Aaron Williams in 2011.

Now with Grimes gone, the Falcons’ secondary returns to its 2011 form, which is a unit that was high on risk taking — a charge led by Robinson — and therefore relatively high on interceptions (19 last year), but low on the ability to stop significant chunk yardage on passing plays after they gave up 56 receptions for 20 yards or more (24th in 2011). Samuel is aging even though he still loves him some good thickness, and Andy Reid thought he was losing a step. And even with a healthy Grimes last year the Falcons still gave up 236.6 passing yards per game.

Immediately anyone who owns Peyton Manning and has become addicted to the Pey Pey Kool-Aid after last night should be pitching a tent of some kind. After passing for 253 yards with two touchdowns and finishing with a passer rating of 129.2 in Denver’s win over the Steelers, Manning gets the first crack at a depleted Falcons defensive backfield next week. Therefore, expectations should also be raised for Demaryius Thomas.

Then just go down the list of the Falcons’ remaining opponents, and what a list of receivers it is. Carolina’s Steve Smith will take two turns, Robert Griffin III and Pierre Garcon will be up in Week 5, and both the Cowboys and Eagles will have one less elite defender shadowing their deep threats.

But Calvin Johnson owners may have the deepest and heartiest laugh late in the year, just in time for the jolly holiday season. The Falcons visit Detroit during Week 16, or as it’s known in the fantasy community, championship week.