NFL

Ross, Webster injuries could put Dockery at CB

It’s on to Plan C at CB.

The Giants are headed in that direction for Monday night’s game at Washington after Aaron Ross missed yesterday’s practice with a left hamstring injury. Ross was likely going to start in place of Corey Webster (knee) and now both are likely game-time decisions for coach Tom Coughlin, putting Kevin Dockery in position for a start.

The game of musical corners to play primarily alongside Terrell Thomas comes after a beleaguered secondary was torched by Tony Romo and Donovan McNabb in successive weeks.

Ross missed the first nine games this season with a pulled left hamstring — which is how Thomas became a starter in the first place — and Coughlin said he believes it’s the left hammy that is again hurting. Ross, who started at safety last week against the Eagles, sustained the latest injury near the conclusion of Thursday’s practice.

GIANTS BLOG

“I’m sure [Ross] is incredibly frustrated,” defensive coordinator Bill Sheridan said. “He’s a competitive kid, and I don’t think there’s anything he likes more than playing football. It’s been another tough break, but hopefully he won’t be out for very long.”

Dockery, a four-year veteran, has played just eight games this season and could be inching toward the end of his Giants career — he is not signed beyond this season. He said Monday could be one of his last chances to prove he belongs for 2010.

“I, just like the team, we both have a lot at stake here,” Dockery said. “It’s Monday night, primetime, a divisional game, so I’m definitely jacked up. I’m very familiar with [the Redskins] and their offense, so it’s just a matter of going out there and executing.”

Rookie Bruce Johnson also could figure into the mix at cornerback. The latest shuffle comes just as the Redskins passing attack is peaking: Jason Campbell has seven touchdown passes and three interceptions over the last three games. That included a 16-for-28 performance against Oakland last week in which he threw two touchdowns without an interception. Santana Moss (53 catches, 700 yards) is Washington’s top receiving threat.

“We’ve got a lot of people on this team who can play, so [Monday] will definitely be a challenge for us, but it won’t be a step down,” Thomas said.

Ross replaced C.C. Brown at safety last week, but Sheridan said he wouldn’t have any problem going back to Brown against the Redskins.

“The reason we played Aaron at safety was an attempt to get him on the field,” Sheridan said. “We thought our corners had played solid and we didn’t see unseating any of those guys and putting Aaron in there, because he had been out so long.

“You have some new pieces that are going to fit in. But these guys have been taught the principles of the coverages from the start, so it’s not like they are starting from scratch. But you have a couple of guys nicked up and it’s not the same as having the guys you’ve been playing with.”

mpuma@nypost.com