The St. Louis Cardinals selected Martini in the seventh round, with the 230th overall selection, of the 2011 MLB draft.[7][1] He made his professional debut with the Low-A Batavia Muckdogs. In 2012, he played for the Single-A Quad Cities River Bandits, slashing .266/.361/.344 with two home runs and 52 runs batted in (RBIs). The next year, Martini played for the Single-A Peoria Chiefs, batting .252/.339/.329 with two home runs and 36 RBIs. He split the 2014 season between the High-A Palm Beach Cardinals and the Double-A Springfield Cardinals, posting a .260/.337/.385 batting line to go along with career-highs in home runs (7) and RBI (60). In 2015, Martini played for the Triple-A Memphis Redbirds and Springfield, accumulating a .285/.392/.407 batting line with six home runs and 46 RBIs. The next season, he again split the year between Memphis and Springfield, slashing .259/.352/.354 with five home runs and 39 RBIs. He returned to Memphis and Springfield for a third straight split year in 2017, posting a .294/.382/.423 slash line with career-highs in home runs (8) and RBIs (70).[8] After playing for seven years in the Cards’ Minor League Baseball (MiLB) system,[9] he was granted free agency on November 6, 2017.[7]
Oakland Athletics
On January 10, 2018, Martini signed a minor league contract with the Oakland Athletics organization. He was assigned to the Triple-A Nashville Sounds to begin the season. On June 6, 2018, Martini was selected to the 40-man roster and promoted to the major leagues for the first time.[10] On June 23, Martini notched his first career hit, which drove in the winning run in a 7–6 victory over the Chicago White Sox.[citation needed] On September 20, he hit his first big league home run off Los Angeles AngelscatcherFrancisco Arcia, who had been summoned to pitch in mop-up duty in a 21–3 blowout victory by the Athletics.[11] Martini finished the season with a slash line of .296/.397/.414.
The Athletics optioned Martini to the Triple-A Las Vegas Aviators before the 2019 season, where he played until he was called up on July 22. He pitched the eighth inning of a July 22, 11–1 loss against the Houston Astros, giving up two walks but no runs, and was returned to Las Vegas the next day. On August 25, Martini was designated for assignment after going 1-for-11 in six major league games.[12]
San Diego Padres
On August 28, 2019, Martini was claimed off waivers by the San Diego Padres.[13] In 26 games for the Padres, Martini logged a .244/.344/.317 batting line with five RBIs. He was designated for assignment on November 20, 2019.[14]
Philadelphia Phillies
On November 25, 2019, Martini was claimed off waivers by the Cincinnati Reds.[15] He was designated for assignment by the team on January 8, 2020, following the signing of Shogo Akiyama.
On January 14, 2020, Martini was claimed off waivers by the Philadelphia Phillies.[16] He was designated for assignment on February 15.[17] He was outrighted on February 19 and invited to Spring Training as a non-roster invitee.[18] Martini did not play in a game in 2020 due to the cancellation of the minor league season because of the COVID-19 pandemic.[19] He became a free agent on November 2.[20]
Chicago Cubs
On January 2, 2021, Martini signed a minor league contract with the Chicago Cubs organization.[21] On May 7, 2021, Martini was selected to the active roster after Ian Happ was placed on the injured list.[22] Martini went for 1-for-12 with one RBI in 12 games before being designated for assignment on June 5.[23] Martini was outrighted to the Triple-A Iowa Cubs on June 7.[24] On September 8, Martini was re-selected to the 40-man roster.[25] Martini was again outrighted to the Triple-A Iowa Cubs on October 3. He elected free agency on November 5, 2021.
NC Dinos
On December 21, 2021, Martini signed with the NC Dinos of the KBO League for $550,000 in salary and signing bonus, with an additional $250,000 possible from incentives.[26] Martini played in 139 games for the Dinos in 2022, slashing .296/.365/.461 with 16 home runs, 85 RBIs, and 12 stolen bases. Martini was named an All-Star for the Dinos in 2022[27] became a free agent after the season.
Cincinnati Reds
On February 3, 2023, Martini signed a minor league contract with the Cincinnati Reds organization.[28] In 93 games for the Triple–A Louisville Bats, he hit .275/.393/.481 with 15 home runs and 65 RBIs. On August 22, the Reds selected Martini's contract, adding him to the major league roster.[29] In 29 games for Cincinnati, he batted .264/.329/.583 with six home runs and 16 RBI.
Martini made the Reds' Opening Day roster in 2024 and hit two home runs on Opening Day.[30] On July 10, 2024, Martini underwent surgery to repair ligament damage in his thumb. He had suffered the injury while sliding into second base in a July 6 loss against the Detroit Tigers.[31] Martini was activated from the 60–day injured list on September 24.[32] In 52 total games for Cincinnati, he slashed .212/.272/.370 with five home runs and 24 RBI. On November 1, Martini was removed from the 40–man roster and sent outright to Louisville.[33]