All season, we’ve stuck our Challenge Tracker on the bottom of this Dirty Laundry post with only a few mentions of the plays involved. It’s been interesting to watch the development of challenge frequency -- Green Bay coach Mike McCarthy, for example, has thrown nearly three times as many red flags as Detroit coach Jim Schwartz -- as well as the success rate.

I thought McCarthy faced a particularly interesting decision in the first quarter of Monday night’s game against Baltimore. As you might recall, Packers tailback Ryan Grant appeared to fumble as he was tackled by Ravens linebacker Dannell Ellerbe at Green Bay’s 17-yard line. Ravens cornerback Domonique Foxworth recovered at the Packers’ 21, giving Baltimore what appeared to be excellent field position in a one-score game.

Watching the play live, I thought Grant’s right knee touched the ground before Ellerbe pulled the ball out of Grant's left hand. Early replays, however, showed that it was at best a bang-bang play. McCarthy saw those replays on the video screen at Lambeau Field and threw the flag. Grant, after all, has fumbled only four times on running plays in his 727-carry career. All of them came last season.

When challenging a play, one criteria every coach must keep in mind is that officials need to see conclusive evidence of a mistake before reversing it. If it’s close or there are other mitigating factors, the call should be upheld.

Watching the play over and over, I really had a hard time deciding for myself if the ball was on its way out before Grant’s knee touched. It was that close. You could really see the call going either way. In this case, McCarthy’s gamble paid off when Walt Anderson reversed the decision and returned the ball to the Packers.

Even though the possession ended in an interception, the reversal created a huge shift in field position. Instead of taking over at the Packers’ 21-yard line, the Ravens started their drive their own 10.

Coaches aren’t going to win that challenge every time, but it was worth the attempt in what McCarthy probably figured was going to be a low-scoring, defensive-dominated game.

Now, on to our aforementioned Challenge Tracker: