According to Kotaku, a Sony spokesperson confirmed layoffs at Zipper, characterizing them as “normal business practice and a result of cutting back on production resources after the launch of two major franchises.”
It’s common for temporary contractors hired by a developer to be laid off after a game’s release, though 33 seems to be a lot more substantial than that kind of layoff. SOCOM 4: Navy SEALs did poorly in release, which could have led to a cost-cutting effort.