DETROIT -- Detroit Lions safety Tracy Walker is done for the day with a knee injury suffered during the third quarter against the New York Giants.
Walker has been one of Detroit's top defenders this season. He entered Sunday third in the NFL in solo tackles with 43 and tied with Cincinnati's Shawn Williams with the most solo tackles by a defensive back.
If he misses any time, that's a critical blow to a Lions secondary that traded away starting safety Quandre Diggs to Seattle earlier this week and saw star cornerback Darius Slay miss Sunday's game against the Giants with a hamstring injury.
When he departed the game with 4:54 left in the third quarter, he was leading the Lions with six tackles against the Giants.
He entered Sunday as Detroit's leader in solo tackles (43), total tackles (50) and tackles for loss (five) along with defending four passes and intercepting another.