Imagine being Joe Nathan 15 months ago.

Imagine feeling a sharp knife-point pain in your elbow, and realizing right away what had happened. Imagine facing another serious surgery, far more complex than your first one, and knowing that at least a full year of drudgery awaited, more than 12 months of mind-numbing repetition and toil, all of it with the increasingly creaky body of a 40-year-old.

Lots of people imagined they were in Nathan’s uniform back then. And the greatest relief pitcher in Twins history knows what they concluded.

“Absolutely nobody believed in me at that point,” Nathan, now 41, said by phone last week from the Iowa Cubs clubhouse, where one of the most unlikely comeback stories in recent history is unfolding. “People assumed I was retiring. Reporters were saying my career was over. People can have their opinions, but the only one that matters is what you believe in yourself.”

And what Nathan believed is: He had not yet achieved what he set out to do, and he wasn’t going to stop until he has.

As big a challenge as a second Tommy John elbow surgery to repair his right ulnar collateral ligament is, as complicating as a flexor tendon detached from the bone made things, as dreary as the prospect of nothing but daily rehab drills can be, none of it is as big a hurdle as the one still ahead: getting to the World Series.

“I’ve been to the postseason six times and we’ve never won a series,” Nathan said. “That’s why I play the game, and that’s why I wasn’t ready to give up. Nobody wants to go out that way” — by breaking down during an April 2015 rehab appearance at Class AAA Toledo — “and that became a huge motivating factor. It’s what got my butt to the gym every day, kept me working at it. I knew I could still help compete for a championship.”

Looks like he will get that chance. Nathan, whose 377 career saves are eighth-most in major league history, signed with the Cubs after a tryout in May, began pitching in the minor leagues (for the Tennessee Smokies, the Cubs’ Class AA team just minutes from his Knoxville, Tenn., home) in June, and he could arrive at Wrigley Field as soon as this week. With former MVP Justin Morneau activated Friday by the White Sox, Chicago could be the site of two remarkable comebacks for former Twins this summer.

Nathan has been encouraged by how well his arm and new elbow feels; with his typical optimism, he makes his first Tommy John surgery, back in 2010 while with the Twins, sound like a positive. “I’ve got experience at this, so it helps me get through the doubts that creep in,” he said. “I know how it should feel each step of the way. It’s been 15 months now, and it feels really good, so I’m pretty positive that it’s coming around.”

The Twins’ all-time save leader can occasionally touch 93 miles per hour with his fastball, throw 92 routinely, and even his slider, always the last pitch to come around during his prime in Minnesota, has begun to dive into the dirt. “The shape of my pitches is coming around. My command is coming around,” said Nathan, who has even learned a changeup. The biggest challenge, he said, is “I forgot how to warm up. It takes me longer now, 45 minutes to get ready to pitch, to stretch, and I threw too many pitches in the bullpen.”

Still, he gave up only two runs in seven relief appearances in Knoxville, and on Thursday he struck out two of the three hitters he faced in his one-inning Class AAA debut in Des Moines. Now he’s waiting for an opportunity with the Cubs, who have been encouraged by his results, and it doesn’t have to be in the ninth inning.

“I know how good that team is with or without me. They’re fun to watch,” Nathan said. “I told [Cubs President] Theo Epstein that I’m not coming into this with any expectations other than helping them with anything they need, sixth-inning, mop-up, whatever. I just want to win.”

CENTRAL INTELLIGENCE

Who has been the Twins’ best pitcher through the first half of the 2016 season? Despite his 3-7 record, it was easily Ervin Santana, according to baseball-reference.com’s calculation of wins above replacement (WAR). The rest of the AL Central? You may be surprised by the answer:

Indians: All five starters have ERAs below 4.00, and Corey Kluber has a Cy Young Award. But Danny Salazar has separated himself with his consistent excellence.

In 12 of his 17 starts, he gave up two runs or fewer, and only once did he give up more than four runs.

Royals: Lefthander Danny Duffy spent six weeks in the bullpen until injuries forced him into the rotation. He has quickly become a stabilizer, posting a 3.11 ERA, holding hitters to a .228 average, and only once in 11 starts giving up more than three runs.

Tigers: Rookie Michael Fulmer made his MLB debut with five strong innings at Target Field in May, and he didn’t take long to live up to his status as a former first-round pick. He pushed his ERA down to 2.11 and didn’t give up more than one earned run in any start since May 21.

White Sox: Chris Sale has 14 wins and the All-Star start, but it’s not clear he will finish with the best season of any Chicago starter. While Sale was winning his first nine starts, Jose Quintana was quietly outpitching him for six weeks, with a 1.38 ERA to prove it. But Quintana seems to be tiring; his ERA in June soared to 5.58.

STATISTICALLY SPEAKING

Eduardo Nunez on Tuesday became the 65th Twins player to appear in an All-Star Game, though like Kurt Suzuki two years ago, he didn’t get a plate appearance. Here are the most frequent Twins’ All-Stars:

Rod Carew: 11 games, 11 starts

Kirby Puckett: 10 games, 6 starts

Harmon Killebrew: 10 games, 5 starts

Joe Mauer: 6 games, 4 starts

Earl Battey: 5 games, 4 starts

Tony Oliva: 6 games, 3 starts

Chuck Knoblauch: 4 games, 0 starts

Cammilo Pascual: 3 games, 0 starts

Justin Morneau: 3 games, 0 starts

It shouldn’t have been a surprise that Max Kepler hit the Twins’ first grand slam of the season last Sunday; the rookie outfielder has had twice as many plate appearances with bases loaded than any other Twin. The most frequent batters with three runners on base in the first half:

Max Kepler: 13 plate appearances, 3 hits, 12 RBI, .273 batting average

Robbie Grossman: 6 PA, 2 H, 4 RBI, .333

Kurt Suzuki: 6 PA, 1 H, 3 RBI, .200

Eduardo Nunez: 6 PA, 1 H, 4 RBI, .200

Eddie Rosario: 6 PA, 1 H, 5 RBI, .250

Eduardo Escobar: 6 PA, 1 H, 4 RBI, .200