Gore will report to the Scranton Wilkes-Barre RailRiders, the Yanks' Triple-A affiliate.
The 28-year-old Georgia native was designated for assignment by the Royals on Friday despite a solid start to the 2019 season in a limited role. He posted a .275/.362/.353 triple-slash line with 13 stolen bases across just 58 plate appearance in 37 games.
Gore admitted last week the sporadic starts represented a mental hurdle.
"It's a lot of pressure on me because I know here's my chance, I don't want to blow it," he told reporters. "It's tough. It gets in your head because you know you finally get your chance out there and you don't want to mess up. But you don't want to not be doing anything either. It's your time to shine, so shine."
Gore, a 20th-round pick of the Royals in the 2011 MLB draft, made his debut in the majors with Kansas City in 2014. He spent the 2018 campaign with the Chicago Cubs before returning to K.C., and he's never been able to lock down a full-time starting job in the big leagues.
The Yankees' outfield depth has been tested throughout the year because of numerous injuries. Giancarlo Stanton, Jacoby Ellsbury and Cameron Maybin remain sidelined, forcing journeyman Mike Tauchman into the club's fourth-outfielder role.
New York's 40-man roster is already filled, which is likely the main reason Gore was sent to Triple-A to start his tenure with the organization. There's a good chance he'll be promoted when a 40-man spot becomes available, but it will once again be in a reserve role.
That said, it's possible the speedster, who has 40 steals in 100 career games, could ultimately crack the Yanks' postseason roster thanks to his niche upside as a pinch runner.