Samuel Rutherford McWilliams (born September 4, 1995) is an American professional baseball pitcher in the Milwaukee Brewers organization.

He spent time on the 40-man roster of the New York Mets and San Diego Padres, and was a Rule 5 pick by the Kansas City Royals, but has not yet played in the major leagues.

[4] He made his professional debut with the rookie ball Gulf Coast League Phillies, pitching to a 5.40 ERA in 9 games.

[9] He finished the year split between the High-A Charlotte Stone Crabs and the Double-A Montgomery Biscuits, pitching to a 6–8 record with 101 strikeouts.

[13] Due to changes McWilliams made to his mechanics and repertoire at Tampa Bay's alternate site during the 2020 season, roughly half the teams in Major League Baseball had inquired about signing him after he became a free agent.

[17] He split time between the Double-A San Antonio Missions and Triple-A El Paso Chihuahuas to finish out the year.

[19] McWilliams appeared in 9 games split between the rookie-level Arizona Complex League Reds and Double-A Chattanooga Lookouts, logging a cumulative 0–5 record and 10.13 ERA with 18 strikeouts in 18+2⁄3 innings pitched.