Seahawks cornerback Richard Sherman told NFL Media's Steve Wyche after the game that he had possession of the late fumble by the Rams. NFL vice president of officiating Dean Blandino explained after the game on Twitter that a player coming out of a pile with a loose ball is not evidence of a clear recovery. The replay officials need video proof of a clear recovery, and there were no shots of that. The ball was still loose when it went into the pile.
"We were both fighting for the ball and I ended up with it," Harkey said, via ESPN.com. "As long as one of us ended up with it, that's all that mattered."
We'll probably never know who really got the ball, but this wound up being a case where the call on the field stood because there wasn't great video proof to show it was wrong.