Siani grew up in Glenside, Pennsylvania, and attended William Penn Charter School.
[2] The Cincinnati Reds selected Siani in the fourth round of the 2018 Major League Baseball draft.
[2] After signing with the team Siani was assigned to the Greeneville Reds of the Low-A Appalachian League, where he slashed 288 /.351/ .386 with two home runs and 13 RBIs in 46 games played.
[4] He spent the 2019 season with the Dayton Dragons of the Single-A Midwest League and hit .253 with six home runs, 39 RBIs and 45 stolen bases.
[8] He made his Major League debut later that day, starting in center field and going 0–3 in a 5–1 loss against the Milwaukee Brewers.