Joe Nathan, with 377 career saves, isn’t expected to be the ninth-inning guy, but Dusty Baker and Mike Maddux, who each coached Nathan in his prime, are intrigued. (Jonathan Newton/The Washington Post)

WEST PALM BEACH, Fla. — When Joe Nathan began to throw live batting practice on Wednesday, Nationals General Manager Mike Rizzo started up his golf cart and drove it all of a few yards, just to get a little closer. Dusty Baker, Dan Jennings and Bob Boone leaned against the cage, just behind catcher Jose Lobaton, to get a better look. Many of the former and current scouts in the Nationals front office hovered somewhere around Field 3 as Nathan started to throw. At 42, the man with the second-most saves of any active pitcher is the ultimate curiosity for a team without a clear ninth-inning man.

Neither Rizzo nor Baker nor anyone else knows exactly what they are going to get, so they press their noses to the fence and take note of his delivery. They do not expect to find a closer in Nathan and his twice-repaired right elbow. But maybe, just maybe, they will find someone to bring experience, wisdom, and late-inning depth to their bullpen.

“Everybody keeps talking about he’s 42 years old, but he doesn’t have a 42-year-old arm since he’s been operated on a couple times, and he certainly doesn’t have a 42-year-old body,” said Baker, who managed Nathan as a 24-year-old rookie and admitted he is rooting for him now.

Reliever Joe Nathan warms up with a football before taking the mound, a trick of the trade he learned following two elbow surgeries. (Jonathan Newton/The Post)

Nathan is as affable as he is tall, with a pleasant perspective on the game after 16 seasons spent at its highest level. He throws a football to warm up because it allows him to get loose gradually, with less arm speed than he generates with a baseball, with less torque than he creates when he pitches, a trick of the trade he’s developed after two elbow surgeries.

He is listed at 6 foot 4, and came to camp as lean and toned as any of the younger, lesser-known pitchers whose lockers surround his. He chose number 74 because he was born in 1974, two decades before some of his neighbors in what might as well be called the “non-roster invite corner” of the Nationals’ new clubhouse.

The righty has 18 times as many saves, with 377, as everyone else in that clubhouse combined, more than all but seven pitchers in history. But he does not necessarily need to re-emerge as a lockdown closer to provide value to these Nationals, who could use a proven ninth-inning guy but seem content to break in a new one.

Proven closers like Alex Colome of the Tampa Bay Rays or David Robertson of the Chicago White Sox have been reportedly available, but the Nationals have internal doubts about Colome, and Robertson is owed $25 million over the next two seasons. Even with a glut of catchers from which to deal, the Nationals seem unlikely to trade for someone owed so much. So whether for the ninth, eighth, seventh or beyond, the Nationals need bullpen depth. For now, it seems they will need to find it within.

“[Nathan’s] a proven late-inning guy, so he’s got to be considered for that,” Nationals pitching coach Mike Maddux said. “A spot in the ’pen, late in the game. That’s what I see him competing for.”

Maddux was Nathan’s pitching coach for two seasons in Texas, where Nathan made two all-star teams at age 37 and 38. Then, Maddux inherited Nathan two years after his Tommy John surgery and a season after he suffered through the worst statistical campaign of his Twins career. Now Maddux inherits Nathan two years after his second Tommy John surgery and a season after he made 10 big league appearances with two teams and spent time in the minors.

“It takes you two years to come back,” Maddux said. “You come back, you pitch, and you’re just kind of getting your feet back under you. Then after you pass that test, it’s go time for you.”

Nathan was not sure he would ever encounter “go time” again after his second surgery in April 2015. He said coming back to pitch in the majors was not his ultimate goal in the immediate aftermath of the procedure. Getting healthy was. If he could pitch in the big leagues again, great. If not, he wanted to be healthy enough to play catch with his son.

So Nathan pushed through rehabilitation, fighting to beat his doctors’ suggested 18-month timeline. Eighteen months of rehab would allow Nathan to return sometime in October, after the 2016 major league season ended. Eighteen months of rehab, therefore, would have left Nathan waiting and wondering through an entire winter.

“If I didn’t pitch last year, I think it probably would have been near-impossible to sign on with a club coming into this year,” Nathan said. “So I just pushed it ahead a little bit, and fortunately my arm responded to it.”

Nathan spent time with the Chicago Cubs and San Francisco Giants last season, and he did not allow a run in 6 1/3 big league innings while pitching to a 2.35 ERA in 15 1/3 minor league frames. His fastball averaged just more than 91 mph during that brief big league stint, according to FanGraphs. Nathan’s career average velocity is just more than 93.

“I think that was what was important last year, trying to get a lot of firsts out of the way,” Nathan said. “How is my arm going to respond to back-to-back days? How is my arm going to respond to a long inning? Where is my velocity at? Does my curveball still have bite on it? Stuff like that.”

Nationals relief pitcher Joe Nathan throws during workouts on Saturday. (Jonathan Newton/The Washington Post)

Those are the things Maddux, Baker, Rizzo and the rest are looking for now, packed against the fences in the bullpens or lingering conspicuously during Nathan’s live batting practices. They’ve watched Nathan grunt pitch after pitch, and take deep breaths between meaningless pitches on the bullpen mounds. They’ve watched Nathan exhale as he throws, as if these were late-October pitches instead of late-February tosses. Wednesday, those eager onlookers watched Adam Eaton rope a hanging Nathan curveball to right for what would have been a single. Then they watched Eaton take a fastball on the outside corner and cock his head, intrigued.

A few curveballs Nathan threw Wednesday sputtered away in the dirt. A few fastballs sailed. But a growing number of whispers around the newly minted fields are conveying the same sentiment: Nathan looks good. His delivery is smooth. Most importantly, there’s life to the fastball, though Maddux said he has yet to try to get a read on Nathan’s actual velocity.

“For a guy that was hurt, you’re not really looking at location as much as you’re looking for how it’s coming out of his hand,” Baker said after Nathan threw in the bullpen earlier this week. “But he has both. Joe’s looking good. He’s looking very good, actually.”

Baker managed Nathan when he was an up-and-comer with the Giants in the ’90s, and knows what Nathan looks like when he is right. Early spring sessions, when pitchers throw behind screens and batters rarely choose to swing, are hardly a basis for conclusions. That Nathan has bounced back well from one bullpen session to the next, with a day of rest in between, indicates that his elbow is healthy and his rehab stuck.

But Nathan is as curious about his stuff as anyone clamoring to see it. After his first live batting practice session, Nathan walked off the mound and straight toward Eaton, Jayson Werth and Bryce Harper to see what they thought.

Eaton asked what a couple of his pitches were, because they sped by like fastballs but had change-up roll. Nathan told Eaton he was happy he swung, because seeing hitters react is the only way Nathan knows how his stuff is playing. Seeing hitters react will be the only way the Nationals know how his stuff is playing, too. As closely as they watched for the first week of camp, Baker, Rizzo and the rest will watch even more closely next week when games begin, and the true test of Nathan’s 42-year-old stuff begins with them.