Shawne Merriman, chasing down Patriots running back Heath Evans in the AFC Championship Game in Foxboro last January, is out for the season.

The Providence Journal / Bob Breidenbach

SAN JOSE, Calif. — The San Diego Chargers defense may be playing without linebacker Shawne Merriman, but that doesn’t mean the unit is suddenly a pushover.

Merriman, who opted to have torn ligaments in his knee surgically repaired after trying to play in Week One and is now out for the season, is an emotional sparkplug for the Chargers. He isn’t, however, the only San Diego player who can make plays.

“They’re a very physical defense,” New England quarterback Matt Cassel said this week. “The front seven plays hard and they are aggressive. They try to create a lot of pressure at the quarterback position. Their secondary’s doing a great job, and they’ve got some playmakers back there with (Antonio) Cromartie and (Quentin) Jammer, and (Eric) Weddle has stepped in at the safety position. We have to be ready to match their physicality when it comes to getting off the ball, whether it be running the ball or blocking up front.”

Coach Bill Belichick noted this week that the Chargers have been blitzing with their outside linebackers as much, if not more, than when Merriman was healthy, and that their pass rush is just as dangerous.

Left tackle Matt Light said not much has changed.

“It’s pretty much a lot of the same stuff — a lot of pressure, a lot of edge pressure, a lot of guys in and out of the line of scrimmage and a lot of movement. I don’t really think from what we’ve seen on film that they have changed the way they approach each game.”

San Diego still has Shaun Phillips, who has racked up numbers in his own right, but Jyles Tucker, Merriman’s backup, is listed as doubtful for this week with a hamstring injury. Tucker missed the Miami game last week.

The Chargers have 12 total sacks, led by Phillips and Tucker with three each.

Rodney’s return

Tomorrow will be Rodney Harrison’s first game in Qualcomm Stadium since he left the Chargers before the 2003 season. The safety was hurt at the end of the 2006 season and was not in uniform for the AFC Divisional upset the Patriots pulled off in San Diego.

Though he admitted this week that he was initially bitter after being released by the Chargers, he’s looking forward to the chance to return.

“That was my home for nine years” said Harrison. “The San Diego Chargers gave me an opportunity to live my dream and to be part of a Super Bowl team [in his rookie year, 1994] and a team that struggled at times we went 1-15 (in 2001).

“At the same time, it taught me so many valuable lessons. The city embraced me and the fans were always great to me. I was able to do a lot of great things in the community.

“Being that I am playing my first time back there, it’s going to be a special moment because I started my career there. I get a chance to go back and play in front of a lot of family and friends. It should be a fun time."

Smooth transition

Before the team had its last practice at San Jose State, Belichick was asked what it took for the Patriots to move their operation out West for a week.

“Well, some of this (equipment) is San Jose (State’s). But it’s a big operation — all the video equipment, all the training equipment, all of the preparation stuff. Our operations people have done a great job and also those working on the fields here. Moving us from Boston to here and down to San Diego it’s a lot of work, there’s no doubt about it. Those guys are doing a great job and have made it really smooth for us.”

Injury report

New England has listed LB Eric Alexander (hamstring), RB LaMont Jordan (calf) and WR Kelley Washington (ankle) as doubtful for Sunday. . All three did not participate in practice yesterday. RB Laurence Maroney (shoulder) and CB Lewis Sanders (hamstring) both had limited participation in practice and are questionable. TE David Thomas, who missed Thursday’s practice with the flu, was on the field yesterday and removed from New England’s report. The Chargers listed WR Chris Chambers (ankle) and LB Jyles Tucker (hamstring as doubtful), while CB Antonio Cromartie (hip), RB LaDainian Tomlinson (toe), WR Vincent Jackson (knee) and FB Mike Tolbert (ankle) are probable.

smanza@projo.com