He elected to become a free agent in November 2022, and signed a minor league deal with the Oakland Athletics in December 2022.
[2][3][4] He attended Hebrew school and had his bar mitzvah at Congregation Klal Yisrael in Sharon, Massachusetts, where he now lives.
[5][6] As a minor leaguer, to supplement his income during the off-season Fishman gives pitching lessons or works as a strength trainer at a gym.
Fishman was named Division III Upstate Baseball Pitcher of the Week after pitching a no-hitter in his second college start on March 29, 2014.
[3] He was named to the NCAA 2015 Academic All-District 3 Baseball Team as a designated hitter, with a 3.32 GPA and a major in Managerial Economics.
[14] He was also named a 2015 Jewish Sports Review College Baseball All-American with first baseman Simon Rosenbaum and first baseman/outfielder Jeremy Wolf, among others.
[15] In his junior, and final, season with the Dutchmen, in 2016 Fishman led all of college baseball with a 0.41 ERA, and had a 7–0 record with 3 shutouts and a league-leading 85 strikeouts and 11 walks in 66 innings pitched.
[4][13] After the college season, he pitched one game during the summer for the Wareham Gatemen of the Cape Cod League, and was drafted the following day.
[25] He was promoted to the Bluefield Blue Jays of the Rookie Appalachian League on August 20, but did not appear for the team before the end of the season.
[34] Blue Jays pitching coordinator Jeff Ware described Fishman as "the kind of pitcher that gives lefties nightmares at the dish.
[39] On December 10, 2020, Fishman was selected by the Miami Marlins in the first round, with the 12th pick, of the minor league phase of the Rule 5 draft.
[49] After six appearances in Triple–A, in which he logged a 2.79 ERA in 9+2⁄3 innings, Fishman was selected back to the major league roster on August 27.
[50] He tossed a scoreless inning against the Tampa Bay Rays before he was designated for assignment again on August 31, when Trevor Rogers was activated from the injured list.
[53] He was assigned to the Triple–A Las Vegas Aviators to begin the 2023 season, but surrendered 8 runs on 9 hits and 1 walk with 4 strikeouts in 3.0 innings of work.
[54] After beginning a rehab stint with the rookie–level Arizona Complex League Athletics, in which he was 0-1 with a 2.25 ERA and struck out 7 batters in 4 innings, Fishman was released by Oakland on July 1, 2023.
[4] In November 2019, he obtained Israeli citizenship so that he could play for Team Israel in baseball at the 2020 Summer Olympics in Tokyo.
[64][65] He played for Team Israel manager Ian Kinsler, and alongside two-time All Star outfielder Joc Pederson, starting pitcher Dean Kremer, and others.
[65][66][67] Fishman pitched for Team Israel in the 2023 European Baseball Championship in September 2023 in the Czech Republic, and was 1-0 with one save and a 0.00 ERA in three games.