The Washington Capitals are off to a great start for the 2019-2020 National Hockey League (NHL) season. The Caps’ record going into last night’s game with the Philadelphia Flyers was a league best 13-2-4 (13 wins, 2 losses and 4 overtime losses).

One reason Washington is playing so well is veteran defenseman John Carlson, who is leading the team in points scored with eight goals and 21 assists, for a total of 29 points.

It’s unusual for a defenseman to be such a scoring threat. Most defensemen in the NHL stay back and make sure the opposing skaters do not get good shots on net. They leave most of the scoring to centers and wingers such as Jakub Vrana and Alex Ovechkin.

That was certainly true in the early days of the NHL. For example, Doug Harvey of the Montreal Canadiens and New York Rangers won the Norris Trophy seven times in the 1950s and ’60s for being the NHL’s best defenseman. But Harvey never scored even 10 goals in any one season during his 19-season career.

One player changed that: Bobby Orr. Orr arrived at the beginning of the 1966-1967 season as a teenager for the struggling Boston Bruins. Orr was a star right away, being named the Rookie of the Year in his first season and the NHL’s best defenseman in his second and third.

In his fourth NHL season, however, Orr took off. He led the NHL in scoring with 33 goals and 87 assists for a total of 120 points. No defenseman other than Orr has ever led the NHL in points scored. Orr also led the Bruins to their first Stanley Cup championship in almost 30 years.

But Orr was just getting started. He scored more than 100 points in each of the next five seasons. In 1974-1975, he led the NHL in points scored again with 135 points (46 goals and 89 assists). That season, he also won his eighth Norris Trophy.

Sadly, Orr’s magnificent career was cut short in his 10th season at age 27 by a serious knee injury. He played only parts of two more seasons.

But Orr had changed the game of hockey by setting NHL defensemen free. He had shown with his lightning rink-length dashes and brilliant stickhandling that a defenseman could be an offensive force while scrambling back to help on defense.

Others followed Orr’s example. Paul Coffey was one of the fastest skaters in NHL history. He topped Orr’s record for goals by a defenseman when he put 48 pucks in the nets for the Edmonton Oilers during the 1985-86 season.

Denis Potvin (1973-1988), Ray Bourque (1979-2001) and Brian Leetch (1987-2006), as well as others, were defensemen who could also score.

Now Carlson is scoring big time for the Washington Capitals. He’s following the example of Bobby Orr.

Correction: An earlier version of this story incorrectly stated that Ray Bourque played in the NHL from 1997 to 2001. He played from 1979 to 2001. The story has been updated.