Role players aren’t supposed to last in one city for a decade. They aren’t supposed to have weekly sports-radio spots, they aren’t supposed to get engaged to Hollywood celebrities, and they aren’t supposed to inspire plush dolls and befriend rock stars and prompt way, way too many blog posts.

Role players also aren’t supposed to be paid like stars. When they are, they might be traded away to free up necessary cap space around midnight on a Sunday. And when a role player is traded away to free up necessary cap space around midnight on a Sunday, and that news makes you stare at your ceiling and think about the past 10 years of your life, you might realize that franchises employ different sorts of role players.

Brooks Laich’s role with the Caps, by the end, couldn’t match his $4.5 million cap hit. His role in Washington, though, went beyond manning the fourth line and the penalty kill. He was hockey’s happy evangelist, the guy who couldn’t stop talking about his sport’s place in this market and in his life. He was the guy who wanted to explain what hockey meant, and how hockey felt; how much it hurt and how much he still hoped. I once asked him if he wakes up as the season approaches and thinks,”I feel like playing hockey today.”

“I wake up every morning and say that,” he said. “If I had one day to live, it would start with probably some hockey.”

Some fans rolled their eyes at that sort of farm-boy hockey gospel. Some thought they had read too many Laich quotes and listened to too many Laich interviews, and had not seen enough Laich goals. Some thought it was all a bit of a performance. If it was a performance, though, it lasted more than 10 years without its lead role once breaking character.

Remember, say, the time he described finding un-cashed paychecks among his belongings?

“I’ll never forget it, it was my first bonus check when I was 19 years old, and it was for $46,000,” Laich said. “And I got it, and I looked at it, and my first thought was this is too much money, I can’t accept this. And I just put it in my closet in my apartment.”

Or the time — not long after his famous tire change — that Laich talked about Washington’s crushing first-round loss to Montreal.

“People underestimate how much this stings,” he said. “And it’s because you tried so hard, and it’s because you want it so much.”

Or the time, in the very first weeks of this blog, when he talked about playing hockey outdoors in Saskatchewan.

“We had nothing else to do but go play, have fun, and at the end of the night go home sopping wet and cold for a nice hot chocolate,” he told me. “Kids would stay out — it wouldn’t matter if it was minus-20, minus-30, kids would still be out there. Ski pants, toques, gloves, scarves, they’d be out there.”

Or the time he earned the respect of John Thompson Jr., just by talking about his sport.

“If you want money go to the bank, if you want bread go to the bakery, if you want goals go to the net,” Thompson said, repeating Laich’s words. “You need to tell a lot of other players that in a relation to a hell of a lot of sports.”

Or especially the time he talked about his 2011 decision to re-sign with Washington.

“You start thinking about your future,” Laich said then, while explaining his decision. “And it wasn’t long after that that I had a conversation with my agent and said: ‘Listen, I’ve thought about it, I’ve taken some time away, and I can only picture myself back in D.C. That’s the only place I want to be. So our sole focus should be on trying to get back in D.C.’ ”

He wound up back in Washington, and then wound up spending almost four years as D.C.’s longest-tenured pro. Laich predated Ryan Zimmerman and Kedric Golston here, and he predated his teammate Alex Ovechkin. They were the last two Caps to have worn those blue-black-and-bronze jerseys, the last two Caps who remembered a time before Rock the Red and annual playoff appearances. “He’s been a good soldier here for a long time,” as GM Brian MacLellan put it last week. “Me and u together since my 1st year..We make this team together!” Ovechkin tweeted early Monday morning.

Ovechkin was the star of everything that happened next, but Laich was one of the narrators, a familiar voice saying reassuring things about how bad the playoff losses felt and how much he wanted to try again, while tossing in a few digs at opponents. There was an unintended punchline sometimes — hey, it’s Brooks Laich, offering perspective —  but who’s been a more consistent voice for hockey in this market over the last decade? Has anyone whose full-time job doesn’t involve talking about the Caps on the radio ever talked more about the Caps on the radio?

Media members probably liked him too much, but how do you not like the guy who fills up your recorder while asking questions about your life? Laich and I got engaged a few months apart last year, and he asked me about my wedding far more often than I asked him about his. Along with Matt Bradley and David Steckel, he insisted on calling me “Bloggy,” and he always greeted my arrival in the dressing room by asking, “Is football season over or something?”

The first time I interviewed him, in the fall of 2006, he had just turned 23. His place in D.C. sports was perhaps tenuous, and his future uncertain. I was a lot worse at my job than he was, but I was also youngish and greenish, with no idea how long I’d last. That morning feels like last week: the team trying to rebuild, and The Post trying to go digital on the fly. And then suddenly it’s midnight on a Sunday — 10 years, dozens of conversations and one trade later — and D.C. sports are a little less recognizable.

I talked to Laich for a long time this fall about his engagement. He had spoken before about his occasional troubles separating life from hockey, how the game sometimes consumed every cranny of his existence. His relationship with Julianne Hough changed that, he said, but it didn’t change how he felt about his sport.

I’m so lucky, Dan,” he said. “I mean, the game has afforded me so much. The friends I’ve made, the places I’ve gotten to travel to, the experiences I’ve had, let alone making a living at it. … You know what, I come here, I’m happy. I play with my teammates, and I go home, and I’m happy. I could be the happiest guy on the team.”

The Caps now need to find a new happiest player, and the sport needs a new local evangelist. This team will be able to fill Laich’s role on the penalty kill, and his place on the fourth line. His departure still leaves a hole.