Tampa Bay has had just four innings thrown by southpaws in relief this season, 2⅔ from Jeff Beliveau and 1⅓ from C.J. Riefenhauser, both of whom are currently on the disabled list. Lefty Everett Teaford, who has a 4.25 ERA in 106 career innings, all with Kansas City, is listed on the Rays' roster, but has not appeared in a major league game since 2013.
Tampa Bay does have left-handers Jim Patterson and Jordan Noberto on their roster at Triple-A Durham, who could both be competing with Cedeno for innings at both the minor and major league levels, though neither of them are currently on the Rays' 40-man roster.
Cedeno was acquired by the Dodgers from the Nationals on Wednesday, again for cash, but was designated for assignment because of a lack of room on Los Angeles' 40-man roster.
To make room for Cedeno on their own 40-man roster, the Rays transferred catcher John Jaso to the 60-day disabled list. Jaso has been sidelined with a left wrist contusion since April 7, and there is no timetable for his return, though the move to the 60-day disabled list pushes the date back until at least June. Rene Rivera will continue as Tampa Bay's starting catcher with Bobby Wilson as a backup.
In Cedeno, the Rays have a pure lefty specialist and a guy that has had a rather strange major league career to this point. Cedeno has played in five seasons with the Astros and Nationals, but has just 55 career innings under his belt, 31 of those coming in 2012 with Houston. Lefties have hit just .252/.331/.351 against him while right-handers have hit .339/.409/.532, an OPS split of 260 points.