SEATTLE — You see the swing, a right-handed uppercut on a 92-mph fastball that cleared the left-field fence at cavernous Safeco Field and broke a scoreless stalemate in the sixth inning here last night.

Then you see the catch, a leaping grab on the run at the lip of the warning track in right field, and the on-target heave back to the infield to double a runner off first base in the seventh.

Most of all, you feel the energy created when Shane Victorino reaches base three times and make as good a play as you will see from an outfielder.

And suddenly you realize what the Red Sox have been missing for the past year and a half.

“Tonight was a flashback to two years ago for Vic,” manager John Farrell said after the Sox won for the fourth time in five nights, 2-1 over the Mariners in a game that was as sharply-played as any of their previous 34. “You give him a lot of credit for all he’s been through physically. To see him come back and play an all-around game as he did tonight, he’s a difference-maker when he’s on the field and when he’s healthy.”

It’s easy to forget now, after all the hamstring and quad and knee and hip issues, and after the complicated back surgery last August and the long recovery that followed. But Victorino was one of the Red Sox’ most valuable players — the MOST valuable, according to the wins against replacement (WAR) calculation by FanGraphs.com — during their World Series-winning season in 2013.

At his best, he’s a bundle of kinetic energy, a disruptive force on the bases, a tough out at the plate and a Gold Glove defender. And he’s a clutch hitter, one of only two players with two career grand slams in the playoffs.

Problem is, Victorino can’t be counted on to be at his best anymore. He hasn’t played more than eight consecutive games since the end of the 2013 postseason and only 45 games in all. His body, once a Ferrari of athleticism, is breaking down like an old jalopy, and at age 34, in the final year of his three-year, $39 million contract, it’s reasonable to wonder if the Red Sox would be better off just calling up Rusney Castillo from Triple-A to be the everyday right fielder.

And then games like last night happen.

“I know there’s others that are coming along,” Victorino said, acknowledging the call for the Sox to move on from him. “It’s still a long way from where I want to be. I’m just glad that I’m getting a chance, that they’re sticking with me. But it’s focusing on just staying healthy and being out there and having fun doing it.”

It hasn’t been easy. Even last night, between the home run and the catch, Victorino walked into the clubhouse and told one of the Sox' trainers that his left leg felt “like it wasn’t really firing correctly.” After stretching to loosen his legs and hips, he was able to remain in the game.

Staying on the field will be an ongoing process. Victorino can’t guarantee he will be able to play every day. At this point, he simply hopes to hold up enough to start against left-handed pitchers, which is Farrell’s initial plan for deploying him.

Mostly, Victorino has learned that he must listen to his body and change conditioning habits that he has developed over time.

“I’ve never been a flexible kind of player. I’ve always felt like I needed to be a little tight so that I can be powerful,” he said from a deserted clubhouse, most of his teammates having already left before he emerged from the training room. “I never had that understanding of stretching. You hear about it, you talk about it, but as an athlete, you sit there and go, ‘No, I’ve always been this way. I’ve had success this way, so why should I go away from my bread and butter? I don’t need to be flexible.’

“And now, to be honest with you, one of our trainers had a heart-to-heart with me and kind of explained to me that, hey, this is the kind of process you have to go through and what has to happen for you to understand your body and make that adjustment.”

As Victorino was talking, a replay of his catch appeared on a clubhouse television.

“I mean, honestly,” he said, “I don’t know how I made this play.”

But he made it and kept the game tied for the Sox to grab the lead against Mariners closer Fernando Rodney in the top of the ninth, prompting utility infielder Brock Holt to exclaim, “That play won the game right there.”

Victorino made plays like that all the time in 2013, and the Red Sox have missed him ever since. For one night, at least, it was nice to have him back.

Maybe this time he will stay a while.