The casting issues for this production began in August, when Rolando Villaz‹n, who was to have played Romeo throughout the run, withdrew first from the autumn performances and then from the December dates due to illness.
Alagna was the first to be cast as a replacement; since he was not available for all of the fall dates (being already booked to sing Pinkerton in the Met's Madama Butterfly), Kaiser was released from a contract with Los Angeles Opera in order to make his Met debut as Romeo. (And when Kaiser fell ill before one of those performances, Marcello Giordani was a last-minute substitute.)
The Met announced yesterday that Kaiser will sing the role on Dec. 8 and 20 and that Alagna will play Romeo on Dec. 12 and 15. That last performance will be the first of this season's eight matinees to be simulcast in movie theaters.
As previously announced, Matthew Polenzani will take over the role of Romeo for the run's final two performances, Dec. 27 and 31. So, by year's end, Netrebko's Juliet will have fallen in love with four different men.