He started playing baseball with the Young Israel of Woodmere team in the shul league.[3] In second grade he moved on to the Hewlett-Woodmere District League in 2008. At age 7, he tried out for the Long Island Chargers travel team, and made the team.[3] The team won the 2012 National Junior Baseball League 9U level championship, with him as the starting center fielder as he batted .415 with an on base percentage of .642, and an ERA of 3.20.[3] He was the only Jewish player on the team, and was 4' 8" and the youngest player on the team.[3]
High school
Steinmetz attended the Orthodox Hebrew Academy of the Five Towns and Rockaway (HAFTR), where Steinmetz played baseball.[6][7] He then switched to the Elev8 Baseball Academy in Delray Beach, Florida in March 2021, for two months, after his last season of high school ball with HAFTR was cancelled due to the pandemic.[8][7][4] His travel team was the Long Island Titans Body Armor, with whom he was named the Most Valuable Pitcher as it won the 2020 PG Super25 17u Northeast Super Qualifier Championship.[9][3][4]
Steinmetz was accepted at Fordham University on scholarship, to play NCAA Division I baseball.[10][7] He decided instead to play professional baseball.[11] Perfect Game listed him as the No. 88 overall prospect (including players from college, junior college, and high school) in the 2021 MLB Amateur Draft.[4]
Arizona scouting director Deric Ladnier said the team liked his "delivery, body, spin rates, plus-velo.... a curveball that ... as far as the spin rates ... it's legitimately power stuff. And obviously he's got the body and the size and the projection for what you're looking for... [he's] supremely talented... we weren't taking him to make this impactful statement [by drafting an Orthodox Jewish player]. We were taking him because of his physical ability."[23] In 2021 Steinmetz pitched one inning in the minor leagues at 17 years of age for the Arizona Complex League Diamondbacks.[24][25]
In January 2022, Steinmetz was rated Arizona's #25 prospect, and he was noted for his strong curveball (which ESPN described as "knee-buckling") and a 97-mph fastball.[26][27][15][28] In 2022, he pitched for the Arizona Complex League Diamondbacks at 18 years of age. He was 0–7 with a 7.88 ERA in 11 games (7 starts). He pitched 24 innings and struck out 27 batters (10.1 strikeouts per 9 innings).[12]
Steinmetz hails from Woodmere, New York and is Orthodox Jewish, keeping the Jewish Sabbath (which runs from sundown on Friday to sundown on Saturday—during which time he will play, but walk to and from the stadium, and not ride in a car, bus, or plane), and eats only kosher food.[23][18][30][28][31][32]
The Diamondbacks and Steinmetz put in a lot of effort in order to accommodate his religion and baseball such as the ordering of kosher food.[33]