The cub farther back (our right) is a male Bengal hybrid that was confiscated at the nearby Tijuana border crossing from someone trying to bring it into the country without a permit. US Fish and Wildlife placed it with San Diego Zoo temporarily (and zoo placed it at Safari Park).
The cub that is closer (our left) is a male Sumatran that was born at National Zoo but rejected by his mother. He was sent to Safari Park to be a companion to the first one.
I was shocked to learn that if you include these two, the park currently houses 11 tigers! The other nine are all Sumatran.