The team also announced minor league infielder Curtis Mead was acquired in a trade that sent left-hander Cristopher Sanchez to the Philadelphia Phillies. In addition, five prospects were added to the 40-man roster before Wednesday night's deadline.
A .282 career hitter, Duffy played just 46 games this year after starting the season on the injured list with left hamstring tightness. It was the third time in the past four seasons he missed significant time because of injuries since being acquired from the San Francisco Giants at the 2016 trade deadline.
De Leon is a 27-year-old right-hander who made three relief appearances over four stints with the Rays after spending the first half of the 2019 season rehabbing from Tommy John surgery. Sanchez, 22, split time this year between Class A affiliates Bowling Green and Charlotte and Triple-A Durham.
Mead is a 19-year-old infielder who hit .285 with four homers and 19 RBI in 44 games with the rookie-level Gulf Coast League Phillies this year.