Since 2003, Rodney Harrison has been the pulse of the Pats’ defense. Says Bill Belichick: “We’ll have to count on a lot of people to do some of the things Rodney did.”

The Providence Journal / Glenn Osmundson

FOXBORO — The New England Patriots have lost two quarterbacks this season.

On Sept. 7, they saw Tom Brady, the quarterback of the offense, lost for the season because of a torn ACL.

On Monday night, they saw safety Rodney Harrison, the quarterback of the defense, lost for the season because of a torn quadriceps.

The Patriots officially placed Harrison on injured reserve yesterday, a move that not only put an abrupt halt to his 15th NFL season, but may spell the end of his standout career.

In the New England locker room, the reaction to Harrison’s injury centered mostly on sympathy for the team captain, who was an emotional leader on the field and a big brother to many players off it.

Versatile Ray Ventrone, a formerly undrafted rookie who began his time with New England as a defensive back, called Harrison a good friend in addition to a good teammate.

“He taught me a lot, not just on the field, but off; how to approach each week, the weight room, how to take care of my body. He’s just a great role model. I’m sorry for him because he works so hard,” Ventrone said.

Each player commented on Harrison’s consistency: That the take-no-prisoners style of play he had on Sundays wasn’t just confined to game days. It was there in practice, too, when he was getting reps with the scout teams.

“What you see in games is what he’s consistently doing in practice,” Ellis Hobbs said. “He’s still practicing with practice-squad special teams. You can’t get rookies to participate in practice-squad special teams sometimes.”

During the team’s recent week in California, Harrison took Ventrone and Eric Alexander out for sushi. One of the topics of conversation, as it frequently is, was Harrison telling the younger players about getting an edge.

“He’s always talking about getting ‘the edge,’ ” Ventrone said. “Whether with film study or weightlifting, treatments on your body, hydration. Just little things. He’d be drinking a bottle of water or something and joke that he was getting the edge on us.”

Harrison recently recalled one of his first practices with New England in 2003, when Troy Brown, coming off a 97-catch season, came across the middle. He tackled Brown hard. Brown threw the football at Harrison.

In a way, that was Harrison announcing himself to his new teammates. At the start of that regular season, he was elected a team captain.

Ever since, he has been the pulse of the defense.

Even this year, as he began the season a few months from his 36th birthday, he continued to play a huge role in the Patriots’ defense. By one count, he had been off the field for just 13 defensive plays through the first five-plus games.

It may take three or four, or more, players to fill the void left by Harrison.

“I think we’ll have to count on a lot of people to do some of the things that Rodney did,” head coach Bill Belichick said. “Rodney had a lot of different roles for us defensively, so I’m sure there won’t be any one person that will do what he did. We’ll have to combine and use a number of people.”

Heath Evans’ thoughts likely summed up those of many Patriots:

“It’s one of those ones where you kind of struggle to even place (the significance) into terms, but I think emotionally is probably where you can’t replace him,” Heath Evans said. “What he brings to practice, what he brings to this team on game day, and then you get into his years of leadership, years of playing this game — the loss is huge. He’s a player that I wish I could be more like him on the field. He’s someone that plays with his reckless abandon but still seems to find a way to be in control and make plays.

“I can’t say enough good things about him.”

smanza@projo.com