LOS ANGELES, July 27 (UPI) -- William Petersen joined the list of "CSI" actors missing from the Hollywood set, but unlike others involved in pay debates, Petersen was sick.
Petersen failed to show up for work on the "CSI" set beginning in early July because he had been diagnosed with an irregular heartbeat, his publicist, Jennifer Allen, told E! Online.
Although Petersen, who plays crime lab boss Gil Grissom, was not hospitalized, the 51-year-old actor was told to rest following the diagnosis.
Petersen's illness coincided with the firings, and subsequent rehirings, of George Eads and Jorja Fox, who were involved with pay disputes with CBS executives.
Petersen reportedly was lobbying for a substantial pay raise, too, but his absence was not linked to negotiating tactics.
A CBS doctor reportedly discovered Petersen's medical condition.
Petersen, Eads, Fox and the rest of the "CSI" cast were to start filming series' fifth season Wednesday.