After Esposito was put on indefinite medical leave in October due to her struggle with Celiac disease, CBS said she was "unable to perform the demands of her role" and brought in several guest-stars, including Ramirez, to fill in as the partner of Donnie Wahlberg's Det. Danny Reagan. Esposito called the network's actions "absolutely shameful behavior" and she permanently exited the show in January.
Ramirez's character, Det. Maria Baez, will now be Det. Reagan's full-time partner. "Truly, I never dreamed I would be coming back as a regular," Ramirez told THR. "To say I am grateful is an understatement."
(Full disclosure: TVGuide.com is owned by CBS.)