Jennings signed a minor-league contract with the Yankees on Monday.
Jennings has elected free agency, Brittany Ghiroli of The Athletic reports.
The Nationals designated Jennings for assignment Monday, Mark Zuckerman of MASN Sports reports.
Jennings (1-2) struck out two in a perfect fifth inning Thursday to record the win over the Mets.
Jennings' contract was purchased from Double-A Harrisburg on Tuesday.
Jennings signed a minor-league contract with the Nationals on Monday, Jesse Dougherty of The Washington Post reports.
Jennings was released by the Angels on Tuesday.
Jennings signed a minor-league deal with the Angels that includes an invitation to major-league spring training, Robert Murray of The Athletic reports.
Jennings started Monday's victory over the Cardinals and retired the first batter of the game before removed from the contest.
Jennings will get the start in Monday's game against the Cardinals.