He’s a very good boy. About the finest dog imaginable, by any standard. It’s one of life’s blessings that the dog named Patriot met Mike Krukow.

Together, their six legs are a pretty good team.

Giants fans are well aware of Krukow’s condition, known as inclusion-body myositis, a progressive muscle disorder that affects the legs, arms, fingers and wrists. He revealed his plight in 2014, sending friends, family and the public into a state of depression — until they realized the power of Krukow’s conviction and the fact that he’s the same enthusiastic, witty, informative person widely recognized as the best baseball analyst in the business.

Inside that booth, he’s the master of his domain. Actually getting there is a daily issue, made infinitely easier by golf-cart rides to Oracle Park and back to his apartment a few blocks from the stadium. Out in public, that’s when things really get difficult.

“I’m not stable enough to walk,” said Krukow, who selects from a quiver of exquisite wooden canes each day. “I probably never will be. And I have a lot of anxiety in crowds. I mean, a tremendous amount.”

Krukow’s hands are functioning nicely, but there is profound weakness in his legs. It doesn’t take much to send him crashing to the ground — he has taken a number of alarming falls over the years — so every trip to a market, store or restaurant can be an adventure.

“People come up to me wanting to shake hands, pat me on the back or give me a hug, and that’s great to see,” he said. “But with the thing that I have, I lose my balance so easily. And it’s always the same — I fall backward. I’m constantly looking out for these situations so I can get my back up against a wall.”

Enter Patriot, a service dog who has become Krukow’s constant protector. In a crowd of people, Patriot’s sole responsibility is to create space between his master and the people. He’s not at all threatening or unpredictable; he’s simply a fixture at Krukow’s side, moving at the measured pace, just to prevent those troubling collisions.

As Krukow was to discover, this yellow Labrador is much more than that. He’s a loving and trusted companion who has brought untold joy into the lives of Mike and his wife, Jennifer.

I discovered that firsthand recently when my wife and I were invited to the Krukows’ apartment. As I settled into a chair, I noticed Patriot moving my way from a nearby sofa, easing himself onto my body and settling in, totally comfortable, never better, for a half-hour or so. It was the greatest 30 minutes of my life, animals division.

“That’s what he was trained to do,” Krukow said. “Even if I’m on a really small chair, he’ll figure out a way to get up there and just melt right into you, all 70 pounds of him. He’s like wax. He conforms to you. He’s better than any drug, I’ll tell you that. This dog is better than any prescription you could ever take.”

The Krukows have been dog people since they were married in 1975. They had a beloved golden retriever, Bella, who died at 15 last year, and “we thought we could never have another one,” Krukow said. “We thought about getting a puppy to train ourselves, but with my situation, it wasn’t practical to have a puppy underfoot. If a dog jumps on the back of my legs, I’m goin’ down. I have to avoid that at all costs.”

Krukow had a speaking engagement in September in Marin County, and as he carefully made his way to the podium, a woman in the audience took notice. “I’m with the Canine Companions in Santa Rosa,” she said after his presentation. “I think you might be a candidate for one of our dogs.”

Intrigued, Krukow learned that the Canine Companions dogs spend nine weeks with the litter before being turned over to a trainer. “After 20 months, it’s decided what this animal is best suited for: full-on service dog, seeing-eye dog, therapy dog,” he said. “But I found they’re mostly used to comfort war veterans, men and women coming home without a limb, or two, or three, and suffering from (post-traumatic stress disorder). And I realized, I don’t need a 24-7 dog. These people are way more deserving than I am. So I removed myself from consideration.”

There was another way, as Krukow learned from Mike Scardino, the Giants’ travel coordinator and a longtime member of the organization. Scardino’s wife, Katrinka, is a trainer at the Napa-based Canine Guardians, and she told Krukow, “We might have a dog for you.”

“It wasn’t easy,” Krukow said. “During Patriot’s two-year training period, the trainer fell in love with him. She was only 19 years old and didn’t want to give him up. So she quit training him, and when the company announced it wanted the dog back, they had to go to litigation. But she got him back — at this point, he’s 3 years and about 4 months old — and she agreed to have us meet him.”

Why the name Patriot?

“It’s that way with all these dogs, the way they hook up with the military,” Krukow said. “Patriot, Captain, Major, Glory, like that. Our only requirement was to give him the additional six weeks of training he needed, and once it became apparent that Jennifer would be able to do that, we were able to take him home.”

“After about a month,” Jennifer said, “we realized, oh, my God, this dog is so special.”

It’s difficult to tell who is more smitten, Mike or Jennifer.

“Our five kids are all grown, and you know, moms gotta be moms,” Mike said. “Whether we’re in San Francisco or Reno (their permanent home, moving from San Luis Obispo after three of the kids attended the University of Nevada), she trains the dog, takes him out for walks, or to the ballpark — there was such a void for Jen when we lost Bella. This has totally changed her life, too.”

So how does it all work, when Patriot isn’t creating public space or turning into a big, warm blanket?

“Well, he travels with me on airplanes,” said Krukow, who has limited himself to San Diego, Los Angeles and Phoenix on Giants road trips, reducing his schedule to 110 games per season. “Lays down on the floor underneath me, stays right there the entire flight, gets up when we land. Damnedest thing you ever saw. I was always a big truck guy, but I have a hard time getting into a truck now. So we got a Honda Passport that’s basically for the dog. He gets in there and lays down, so chill. He goes wherever we go. We take him everywhere. And he’s always got the service-dog vest on, so his identity is clear.”

Generally, when a dog is trained to comfort PTSD, “the dogs are trained to get up in bed with them,” Krukow said. “They have these horrific nightmares and the dogs are right there. Patriot really wants to do that with us. We don’t let him up on the bed, but if I have a bad dream — it’s always about a bad inning in Houston (laughs) — he’ll wake me up and I feel a whole lot better. That’s his deal, to figure things out. It’s the best.”

I had my own concerns that night at the Krukows, knowing I was a few days away from knee-replacement surgery. All sorts of dreaded scenarios enter your mind, but the sight of Krukow — the amiable, generous host, wielding his trusty cane — brought home a far broader picture. Here’s a man who was an avid snowboarder and golfer well into adulthood, a retired athlete with a teenager’s stoke, always ready to throw pitches to his kids or visitors in the family batting cage. That’s all gone now, vanished along with the strength of his legs.

And not one ounce of his remarkable spirit has been drained. As we headed for the door, Krukow looked me straight in the eye.

“We are so lucky,” he said.

Bruce Jenkins is a San Francisco Chronicle columnist. Email: bjenkins@sfchronicle.com Twitter: @Bruce_Jenkins1