Does Dan Haren still exist? Or even a reasonable facsimile of him? Or was last year, when he slumped to 12-13 and went on the DL for the first time, a sign that seven years as one of baseball’s most valiant warhorse pitchers had worn out his hip, back and fastball. Next stop: going, going . . .

The Washington Nationals have bigger questions, but not many. If they got something akin to prime Haren, it’s one of the grand thefts of the offseason. If his slide worsens, they burned $13 million and need a fifth starter.

Many assume the 32-year-old Haren is a sensible replacement for Edwin Jackson. He’s not. He’s much higher reward and not-insignificant risk of being worse. A few know how delighted the Nats are to see Haren in their midst. “He’s absolutely fearless,” said Kurt Suzuki, who caught him on the A’s in ’07.

“Has there ever been a better five-man rotation than this one, at least potentially?” said Jayson Werth.

Come on, how can you possibly say that?

After winning the NL East in 2012, the Washington Nationals are coming into the year with a cacophony of hype. But Thomas Boswell says focusing on this year’s potential is missing the point. (Brad Horn/The Washington Post)

“If Dan Haren is your fifth starter,” he said, “how good could you be?”

That’s the high, high side, unlikely but possible. Haren’s whole career has been on the West Coast, away from East Coast eyes. Because he’s been consistently excellent but never won more than 16 games, he doesn’t have the glamour of comparable pitchers. Who’s comparable? Over the last five years, including his poor 2012, Haren has 70 wins and a 3.58 ERA. Zack Greinke, who just got a $147 million contract, won 70 with a 3.42 ERA.

Oh, Haren’s not Greinke, you say. Maybe not, but he’s a true Somebody.

One of baseball’s gaudiest statistics for measuring a pitcher’s stuff plus his command is his strikeout-to-walk ratio. Since 1884, the best whiff/walk ratios have been Curt Schilling (4.38), Pedro Martinez (4.15), Mariano Rivera (4.04) and Dan Haren (4.01). Stephen Strasburg was 4.10 last year.

Only one active pitcher, Roy Halladay, has better control than Haren, who actually ranks slightly ahead of immaculate Mark Buehrle and Cliff Lee with only 1.89 walks per nine innings.

The risk-reward range on Haren is extreme. Among pitchers who most resemble him statistically at 32, Bill Gullickson went 20-9, Jim Bunning 19-8 and Kevin Appier 15-11. But Ron Darling was 5-9 and John Lackey had a 6.41 ERA. This can go either way, very dramatically and with huge ripples.

“If he’s what he was last year, he’s a terrific complementary starter for us,” said Nats General Manager Mike Rizzo. “But he’s only 32. If he’s the guy he’s been every other year except last year, he’s ‘top of the rotation’ elite.” Rizzo doesn’t mention Darling, Lackey or the like. Why get wrinkles in February because Haren’s fastball, never below 90mph before, dropped to 88.5 last year?

“We [evaluators] all worry about ‘old,’ ‘injury prone’ and ‘his stuff isn’t as good.’ ” said Rizzo dismissively. “This is a guy with plus-plus-command of three pitches. His ‘plus pitch’ is his command of all his pitches.

“We’ve done a lot of things with his hip — stretch, different workouts with less weight to bear, masseuse twice a week. He has more range of motion. If that improves, the fastball may improve. But it doesn’t have to.”

Whatever happens, Nats fans will see a classic type — the play-through-pain, pry-the-ball-out-of-my-cold-hand competitor that teammates admire.

“I take a lot of pride in making all my starts,” he said. “I told my wife if I ever come out of a game with an injury, I’m really hurt. Be concerned.”

A reporter asked Haren if it would be smart insurance for the Nats to sign free agent Kyle Lohse. That’s the wrong question to the wrong guy.

“And I go to the bullpen?” Haren said sharply. “I’m not ready to be a long reliever. Lets give it five years.” So, there it is, the real Haren plan.

“I feel great,” added Haren. “This is a big year for me.”

Last year, Jackson blended with the Nats’ staff, but Haren will bring special qualities. “Don’t give the hitter too much credit. Be confident in yourself. Make ’em earn their way on,” Haren said Monday. “I don’t adjust to hitters much. I concentrate on my game. If they hit the first pitch, okay. If I get behind, I’ll get back in the count.

“With the stuff the other guys on this staff have, they should have no fear, no matter the count. Let the pitcher be the one who’s aggressive.”

Since Haren’s locker is between Strasburg and Gio Gonzalez, and because he is a master of getting high strikeout counts (223 one season) by “setting up hitters” and “expanding the zone” — something the young Nats haven’t mastered, it’s assumed that Haren may be a coach in disguise.

“I’m a guy they can turn to when they aren’t going great. But I’m not ‘mentoring’ Stephen Strasburg. It looks like he’s got it down pretty good.”

Nevertheless, Haren is a model total pitcher. In two-plus NL years in Arizona, he hit .265 with a .667 OPS — near the MLB norm for batters and better than ex-Nat Jesus Flores’s career mark (.663). He’s like a free DH. And he led his league in fielding three times with perfect 1.000 seasons.

His defiant mound presence may define him most. “If he gives up a 500-foot foul ball,” said Suzuki, “you know you’re going to see that same pitch pretty soon. ‘Lets see you do it again.’”

Few athletes have as clear a sense of where they stand in their career and what they have to do to get back on top. Can Haren do it? Different question. But this is a pitcher who even knows that the ball flies further at 8 p.m. in Anaheim than it does at 7 p.m.

“As a pitcher ages, his velocity goes down a little. You try not to look at the radar gun. Everybody is so obsessed with it. I tried to get [the velocity] back. I didn’t trust myself and I’d overthrow. . . . That led to injuries,” Haren said. “That was just a struggle. I was trying to get healthy all year.

“Then I had mechanical problems when I came back. I’d never been on the DL before. I was just a mess. Then, at the end of the year, I just pitched like myself and didn’t pay any attention to velocity. Everything was fine.”

In his last eight starts, with an 88-mph fastball, Haren had a 2.81 ERA with 41 strikeouts and only five walks in 48 innings. That’s whom the Nats hope they signed. Or even someone within sight of that Haren.

The patient Haren has gone over every angle of his career tipping point. “I’ve never had a year like that before. So this is a big season for me,” he said. Then, as he walked away, Haren turned back [remember this is a star] and said matter-of-factly, “I’ll bounce back this year.”

Some do. Some don’t. But that could be a mighty high bounce.

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