Answer by taking a quote from the following article:

Saosin is an American post-hardcore band from Orange County, California, United States. The band was formed in 2003 and recorded its first EP, Translating the Name, that same year original vocalist Anthony Green left Saosin due to personal reasons. In 2004, Cove Reber replaced Green as vocalist after auditioning for the role. The group recorded its self titled debut album which was released on Capitol Records on September 26, 2006.

The original lineup for Saosin, consisting of Burchell, Shekoski, Kennedy and Green, was formed in the summer of 2003. On June 17, the band released their first commercial production, the EP Translating the Name. It was an immediate success and was immensely popular on online forums and music sites. Saosin first became popular through promotion and exposure through the Internet. They became known for their distinct musical styles long before their first studio-length album was released, and were popularized on social networking and music sites such as MySpace. The E.P. has sold an estimated 62,000 copies.  Bassist Zach Kennedy left the band early on, as he wanted to pursue a career in art. He was later replaced by Chris Sorenson. A local Southern Califonian drummer by the name of Pat Magrath,  was hired only for the recording for the EP, according to Burchell. The band was impressed with his drumming skills however, and he later appeared as a guest performing Lost Symphonies live with the band. Alex Rodriguez was unable to record Translating the Name as he had promised his band at the time Open Hand he would finish recording with them. Danny King filled in for live drums with the band before Rodriguez completed his responsibilities with Open Hand and joined Saosin full-time after the EP release. Saosin went on a U.S. tour with bands Boys Night Out and Anatomy of a Ghost shortly after the release of Translating the Name.  In February 2004, the band's vocalist Anthony Green left Saosin and later formed the band Circa Survive. Green was homesick, depressed and said he was missing his family. Green was also disenchanted with the direction of Saosin and disliked that the band excluded him from the writing process. The band finished their Warped Tour obligations with Story of the Year's Philip Sneed taking the mic. A public, nationwide audition then took place.

Did anyone join them during this time?
Chris Sorenson.