Lamb, ESPNU's fifth-ranked incoming freshman shooting guard, needed arthroscopic surgery on his left knee to remove a loose body and is expected to be out for 3-4 weeks.
Lamb said he had been dealing with the knee issue for about a year and a half and decided on offseason surgery after consulting with coach Ben Howland.
Anderson, who had a groin injury as a sophomore, suffered a nasal fracture during a pick-up game last week and underwent surgery Thursday.
Returning leading scorer Malcolm Lee suffered a torn meniscus playing basketball in May that required arthroscopic knee surgery. Forward Brendan Lane underwent an ankle procedure in April that could keep him out for the rest of the summer.
Howland himself underwent surgery last month after suffering a ruptured Achilles tendon.
Diamond Leung covers college basketball for ESPN.com and can be reached at firstname.lastname@example.org.