Longstanding pals use the initials, D.R.
Ever since his junior days in Spokane, he's answered to the current nickname of choice, Doc.
But to the precocious Dillon Dube, he goes by …
"Dad," confesses Derek Ryan, with a wistful smile. "Calls me that all the time.
"I mean, how does old he think I am?"
The Yoda-wise Ryan does have an 11-year head start on the young 'un often manning the right side of his delivery-on-demand line.
Acting as the fulcrum between jackhammer-like vet Milan Lucic and lickety-split freshman Dube, D.R., Doc, Dad - whatever you prefer to call him - is enjoying yet another rich vein of two-way form at the moment.
While the Flames have often juggled their personnel and lines this season, that trio frequently skates together.
And when they do, they are always nothing less than reliable, counted upon in so many small, undetectable-to-the-untrained-eye ways, Ryan's skill and ability to make those around him better on full display.
People in this town got a couple glimpses of that sublime mix during Ryan's debut season here.
"There's more of those types of guys in the league than you realize - guys that don't get enough credit in the media,'' reminds Lucic. "They just quietly go about their business.
"You don't see their posters on billboards OR on the side of the arena when you're driving up.
"And then you play with them and you're like: 'Wow!' You don't fully appreciate them until you're there, day after day.
"For me, personally, I've always had the most success with a right-handed centre. Lefty-righty. Left-righty. It's always a forehand pass.
"When you're not the biggest guy on the ice, you have to be smarter than a lot of people. You can see that with 13.
"Derek's underrated. Good on both sides of the puck. His offensive skill is much better than he's given credit for.
"It wasn't a match made in heaven right away between us. We started together. We were broken up. Then we got put back together.
"Adding Dubes to the mix really helped both of us."
Dube can't say enough about the effect Ryan's mentorship has exerted on him.
"Take away what happens on the ice and just take a minute to look at the person he is off it,'' says Dube. "Such a good example to follow, for anyone. He's probably the nicest guy I've ever met. I've gotten to know him. It's not just: 'Hey, how's it going?'
"Coming in every day and just talking to him … I can't tell you how much it's helped me. And now getting to play with him, too, has meant so much, because he's made such an impression on me off the ice.
"I honestly can't say enough about him. That's why Billy (Peters) brought him in.
"Such a good family man. Such a good teammate. Whenever I need something, whenever I need some advice, he's the first person I turn to.
"I have a question, I go to him and I get an answer.
"I feel like his kid every day.
That Clark Kent exterior may be the real, honest-to-goodness Derek Ryan, but he can slip into those superhero tights from time to time.
"Look, I'm not the flashiest player,'' concedes Ryan. "I'm not going lead the league in scoring. I think I'm smart enough to realize that. But I think my consistency allows coaches to use different-style players with me, and I make the guys around me better.
"If the players around me are already good, they make me better, too. A win-win relationship. I feel that's the case with Dillon and Milan.
"Same with Jeff Skinner in Carolina, Mang and Hath last year here.
"A case of when we get comfortable together, we can make each other better.
"I think I'm good at that."
But he underestimates himself.
Quietly, of course, as is the man's custom.
When asked if this, right here, right now, might be considered the finest stretch of hockey he's logged in quite some time, Ryan answers with a tolerant look.
"I'm very happy with the way I've been playing,'' is the measured reply. "Let's put it that way.
"I wanted to hit my stride early in the year, which was a goal. And I think I've accomplished that.
"You know, I get asked that question whenever I'm going through a good offensive stretch. The last couple months of last year, same thing.
"They want to know: 'Is this the best you've ever played?'
"I honestly don't think of it that way. Maybe the media does. Best? What's best?
"I know where my game is at any time and where it needs to be and when it's there I'm just trying to keep it there as long as I can."