Tampa Bay Rays The
Tampa Bay Rays selected Fleming in the fifth round of the
2017 MLB draft. He signed and made his debut with the
Princeton Rays, that year. Fleming's 2017 stat line included a 5.40
earned run average (ERA) across 12 games (nine starts). In 2018, Fleming began the season with the
Bowling Green Hot Rods, where he posted a 1.20 ERA over ten games. Fleming began pitching for the
Charlotte Stone Crabs in July, achieving a record of 3–3 with a 4.11 ERA. In posting a 2019 season record that included a 3.31 ERA over 21 games, Fleming was named the MVP of the season by the
Montgomery Biscuits . He finished the season with the
Durham Bulls, compiling a 5.14 ERA across four games. In July 2020, the Rays added Fleming to their
60-man roster. On August 21, after Rays starter
Yonny Chirinos was ruled out for the rest of the 2020 season with a torn
UCL,
Kevin Cash announced Fleming would be called up to make his debut on August 23, against the
Toronto Blue Jays. His contract was officially selected to the active roster on August 23. Fleming earned the win in his big league debut, pitching five innings with three strikeouts and two earned runs in a 5–4 Rays victory. He finished the season with a 5–0 record and a 2.78 ERA in innings. On July 7, 2021, Fleming combined with
Collin McHugh,
Diego Castillo,
Matt Wisler, and
Peter Fairbanks to no–hit the
Cleveland Indians. However, since the feat was achieved in a truncated seven–inning
doubleheader game, it was not recorded as an official
no-hitter. Fleming made 26 appearances for the Rays in 2021, which included 11 starts. In innings pitched, he logged a 10–8 record and 5.09 ERA with 65 strikeouts and 1
save. In 2022, Fleming made only 10 appearances (3 starts) for the Rays, missing time with an oblique injury. In 35.0 innings of work, he struggled to a 2–5 record and 6.43 ERA with 29 strikeouts. In 2023, Fleming began the year with the Rays, pitching in 11 games before he was scratched from a scheduled start against the
Boston Red Sox and placed on the injured list with elbow soreness on June 2. An
MRI revealed
cartilage buildup on his elbow bone as well as inflammation, and he was transferred to the 60–day injured list on June 10. He was activated on August 12. Following the season on November 4, Fleming was removed from the 40–man roster and sent outright to Triple–A Durham. On November 6, 2023, Fleming was claimed off waivers by the
Philadelphia Phillies. However, he was not tendered a contract for 2024 and became a free agent on November 17.
Pittsburgh Pirates On February 14, 2024, Fleming signed a one-year contract with the
Pittsburgh Pirates. In 17 games for Pittsburgh, he compiled a 5.68 ERA with 13 strikeouts across 19 innings pitched. On May 14, Fleming was
designated for assignment by the Pirates. He cleared waivers and was sent outright to the Triple–A
Indianapolis Indians on May 18. On June 14, the Pirates selected Fleming's contract, adding him back to the active roster. He was designated for assignment again on July 26. Fleming elected free agency on July 28.
Seattle Mariners On August 6, 2024, Fleming signed a minor league contract with the
Seattle Mariners organization. In 19 appearances for the Triple-A
Tacoma Rainiers, he logged a 2–2 record and 4.50 ERA with 13 strikeouts across 16 innings pitched. Fleming elected free agency following the season on November 4. On December 19, 2024, Fleming re-signed with the Mariners on a minor league contract that included an invitation to spring training. He was released by Seattle on June 15, 2025, but re-signed with the organization on a new minor league contract the following day. Fleming made 47 appearances (three starts) for Tacoma, with a 5–5 record and 4.91 ERA with 44 strikeouts and one save across innings pitched. He elected free agency on November 6.
Toronto Blue Jays On February 7, 2026, Fleming signed a minor league contract with the
Toronto Blue Jays. He was assigned to the Triple-A
Buffalo Bisons to begin the regular season. On April 6, the Blue Jays selected Fleming's contract, adding him to their active roster. He appeared in relief that night against the
Los Angeles Dodgers, but allowed four runs on six hits with one strikeout over three innings of work. The following day, Fleming was designated for assignment by Toronto. He cleared waivers and elected free agency on April 9. On April 12, Fleming re-signed with the Blue Jays organization on a minor league contract. ==Personal life==