On April 12, 2016, Grotz signed with the Washington Wild Things of the independentFrontier League.[7] In 29 appearances with Washington, Grotz recorded a 4–2 record and 1.36 ERA with 51 strikeouts in 46+1⁄3 innings of work.[8]
Los Angeles Dodgers
On August 18, 2016, Grotz's contract was sold to the Los Angeles Dodgers organization.[9] He pitched in five games for the rookie-level Ogden Raptors, posting a 4–0 record and 0.50 ERA, but was released on September 18.
Bridgeport Bluefish
On February 14, 2017, Grotz signed with the Bridgeport Bluefish of the independent Atlantic League of Professional Baseball.[10] In 67 appearances for Bridgeport in 2017, Grotz logged a 4–3 record and 3.77 ERA with 80 strikeouts in 74 innings pitched. He became a free agent after the season.
York Revolution
On March 1, 2018, Grotz returned to the Atlantic League, signing with the York Revolution.[11] In 7 games with York, Grotz registered a 2–1 record and 2.53 ERA with 33 strikeouts in 32 innings of work.
New York Mets
On June 15, 2018, Grotz's contract was purchased by the New York Mets organization.[11] He finished the season with the Single-A Columbia Fireflies, pitching to a 3–7 record and 4.61 ERA in 13 appearances. On November 2, he elected free agency.[12]
Seattle Mariners
On February 21, 2019, Grotz signed a minor league contract with the Seattle Mariners organization.[13] He opened the 2019 season with the Double-AArkansas Travelers.[6] On July 31, the Mariners selected Grotz's contract and promoted him to the major leagues for the first time.[14] He made his major league debut on August 2 against the Houston Astros, allowing one run over two innings pitched.[15][16] During the 2019 season, Grotz appeared in 14 games with the Mariners, all in relief, pitching to a 0–1 record with 4.15 ERA and 18 strikeouts in 17+1⁄3innings pitched.[17] He also made two appearances in Triple-A with the Tacoma Rainiers of the Pacific Coast League.[18]
During the shortened 2020 season, Grotz appeared in five games with the Mariners, with no decisions and a 14.73 ERA and four strikeouts in 7+1⁄3 innings pitched.[17] On September 1, 2020, Grotz was outrighted off of the Mariners' 40-man roster.[19] He did not play in a minor league game due to the cancellation of the minor league season because of the COVID-19 pandemic[20] and became a free agent on November 2.[21]
Boston Red Sox
On January 18, 2021, Grotz signed a minor league contract with the Boston Red Sox.[22][23] He was assigned to the Triple-A Worcester Red Sox and spent time on the injured list until making his season debut on June 11.[24] In eight appearances (one start) with Worcester, Grotz compiled a 9.58 ERA while striking out seven batters in 10+1⁄3 innings.[21] He did not pitch after July 10,[24] spending the rest of the season on the injured list.[21] On November 7, he again elected free agency.[21]
Acereros de Monclova
On May 27, 2022, Grotz signed with the Acereros de Monclova of the Mexican League.[21] Grotz did not appear in a game for the team during the 2022 season. In 2023, he made 10 appearances (7 starts) and logged a 2–2 record and 4.42 ERA with 29 strikeouts in 38+2⁄3 innings pitched.[25]
On October 12, 2023, following the American Association season, Grotz was returned to the Acereros de Monclova of the Mexican League.[27] He made 14 starts for Monclova in 2024, compiling a 7–1 record, 81 strikeouts, and a league–leading 2.35 ERA across 76+2⁄3 innings pitched.[28]
