Last night, the 49ers lost to the Giants on a rainy, windy night in the famously inhospitable Candlestick Park. One of the players who struggled the most with the conditions was Kyle Williams, a 49ers receiver and son of White Sox GM Kenny Williams. The team's receiving corps was generally ineffective, but Williams, filling in for injured, experienced kick returner Ted Ginn Jr., took the worst of it:

In the fourth quarter, Williams let a punt drop near him, and the Giants fell on it. The 49ers were originally awarded the ball but replays showed that Williams' knee brushed the football as it landed. Giants coach Tom Coughlin challenged the ruling and the play was reversed, with the Giants getting the ball on the 49ers' 29. Seven plays later, the Giants scored a touchdown — Manning finding Mario Manningham — to retake the lead, 17-14.

The second-year player had other rough moments: a fumble on a reverse that he fell on, a strange sideways diving catch on another punt that could have been disaster. In the rain and wind, it wasn't a fun day to be a relatively novice punt returner.

Ann Killian also notes that Williams lost a lot of his second season to injury; according to Kenny Williams, he had a shoulder injury last night, and he suffered a concussion in Week 16 that kept him in limited practice prior to the 49ers first playoff game. But as New York's Benjamin Wallace-Wells noticed, Willams's recent injuries weren't the half of it. He's been concussed before, and the Giants were all too aware of it:

And the Giants, interviewed in the happy haze of the winning locker room, casually noted a provocative element of their game plan: They'd targeted Williams for extra violence because they knew he had suffered several concussions in the past, and they think it worked.

After the game, reporters crowded around the locker of Jacquian Williams, who'd forced the second fumble, hoping for an angle: Had the Giants noticed something about Kyle Williams's technique, some weakness in the 49ers punt-return scheme? "Nah," Williams said. "The thing is, we knew he had four concussions, so that was our biggest thing, was to take him outta the game."

One Giant, Tyler Sash, himself had to leave the game with a concussion; he was one of the special-teams players enforced with hitting Williams:

Sash, too, made an important play. Early in the game, he hit Williams so hard that it left him woozy. The Giants knew Williams had a history of concussions — it was in the scouting report — and their goal was to disoriented him by pouncing him.

It worked.

"He looked dazed when Sash hit him," Thomas said. "I feel like that made a difference and he coughed it up."

It's a good catch by Wallace-Wells. Concussions were, to my mind, the most important sports story of last year, but the Giants' comments have gone mostly unremarked upon in the excitement over the conference championships.

Did Williams's prior history of concussions play any role in his poor performance? You don't have to be playing with limited faculties to struggle with the ball on a wet night at Candlestick, and Williams is a young player who was pressed into service when the veteran kick returner Ginn went down, not to mention a young player who had lost a lot of playing and practice time to injury. But that's the thing about concussions—their interaction with other elements is difficult to separate out, because they're internal injuries that still remain mysterious to doctors.

Photograph: ankarino (CC by 2.0)