Devin Smeltzer was 9 when doctors found a tumor the size of a grapefruit in his bladder.

The fourth grader went through months of treatments. He lost his hair. He had no appetite for anything but garlic croutons and Doritos. He didn’t get a feeding tube implanted, because that would take away his true love: baseball.

His doctors let him take the field that fall despite his treatments, which exhausted but exhilarated him. And it helped his body respond to chemotherapy. After nine months, he was mostly back to normal. But he wouldn’t be declared cancer-free until 2012, when he was 16 and playing for Bishop Eustace. Just in time for him to begin pursuing his dream: becoming a major-league pitcher.

Smeltzer saw it come true on Tuesday night.

The 23-year-old lefthander made his MLB debut for the Twins, allowing just three hits, no walks and no runs while striking out seven in Minnesota’s 5-3 win over the Brewers.

In the stands at Target Field were his parents, Christina and Tim, and about 20 other friends and family members.

The Smeltzers, who live in Voorhees, were filled with emotion while watching their son. Christina told Fox Sports North she cried with every pitch in the first inning. Tim said his heart was jumping out of his chest.

“It’s everything he wanted. His whole life, this is it.”

In part, Smeltzer credits his battle with cancer for his success.

“I am the person I am today because of what I went through,” he told the Daily News in 2016.

Read more about Smeltzer’s journey in this Marcus Hayes column.

Smeltzer was first drafted out of Bishop Eustace in the 33rd round in 2014 by the Padres. He chose to play at Florida Gulf Coast instead, then transferred to San Jacinto Junior College in Texas to be eligible immediately. He was drafted again after his second college season, going in the fifth round in 2016 to the Dodgers.

While with Los Angeles, he was reunited with former Phillies great Chase Utley. Smeltzer first met Utley when the second baseman, still with Philadelphia, signed an autograph for 10-year-old Smeltzer during a visit to Citizens Bank Park.

He reached as far as double-A Tulsa as a member of the Los Angeles organization before being traded to the Twins in July 2018. At the time, he had been working as a reliever. He wanted to be a starter again, and he told the Twins brass that.

He began 2019 at Double-A Pensacola and was promoted to Rochester after five games. In his four starts with the Red Wings, he had a 1.82 ERA. An opening came up when the Twins placed Michael Pineda on the injured list on Tuesday.

Smeltzer’s story resonated with the Twins television broadcasters, too. Hall of Famer Jack Morris got choked up when talking about Smeltzer’s journey, telling the story of what an amateur coach said about the pitcher.

I never had to tell him anything because he had the heart to do it," the coach said. “... He’s had to fight through a lot.”