[5] After the Second World War ended, Niarhos returned to the Yankees organisation in 1946, playing for Kansas City Blues of the American Association.

Niarhos returned to the minor leagues in 1947 where he hit for a .321 batting average in 93 games for Kansas City, prompting Blues manager Billy Meyer to describe him as, "the best catcher in the organisation.

"[6] This was high praise in an organisation that included future catching standouts such as Yogi Berra, Sherm Lollar and Aaron Robinson.

[1] He served as a reserve catcher behind Phil Masi in the 1951 season before being traded to the St. Louis Browns for Sherm Lollar at the end of the year.

[11] He spent two seasons as a reserve catcher for the Red Sox before ending his major league playing career with the Philadelphia Phillies.

[12][13][14] As a manager in the Athletics minor league system, he coached future stars such as Reggie Jackson, Vida Blue, Rollie Fingers, Tony La Russa, Gene Tenace and Catfish Hunter.