Jonathan Penner, Michael Skupin and Russell Swan's Survivor returns are now official.

CBS has formally announced Penner, Skupin and Swan will be the three former Survivor castaways who will be -- unlike last season's Survivor: One World edition which featured all new castaways -- returning for a another chance on Survivor: Philippines, this fall's 25th Survivor edition.

The three returning Survivor castaways had all been medically evacuated from the game during prior Survivor seasons and will compete in Survivor: Philippines against 15 new castaways.

Survivor: Philippines -- which was filmed in March and April -- is the second Survivor edition for Skupin and Swan and the third Survivor edition for Penner.

Penner originally competed on Survivor: Cook Islands in 2006, finishing seventh. He then returned to compete as a "favorite" on Survivor: Micronesia -- Fans vs. Favorites, the "half all-stars edition" which aired on CBS in early 2008, but was medically evacuated from the game during the sixth episode after he developed a life-threatening infection in a knee that was punctured during one of the competition's challenges.

Skupin competed on Survivor: Australia, the second Survivor edition which aired on CBS in early 2001, and was arguably the subject of Survivor's most memorable injury ever. Similar to Penner, he was medically evacuated from the game during the season's sixth episode after he passed out and fell into his tribe's campfire and severely burned his hands. 

Swan competed on Survivor: Samoa in 2009 and, like Penner and Skupin, was also medically evacuated during his season's sixth episode. In his case, he collapsed while blindfolded during a Reward Challenge after he had exhausted himself attempting to lead his tribe by example in performing chores around camp.

Online reports that Penner, Skupin and Swan were the three castaways returning for Survivor: Philippines have circulated since this past spring.

CBS had announced three former Survivor castaways who were medically evacuated would compete on Survivor: Philippines during May's broadcast of Survivor: One World's reunion show. During the announcement, Survivor host Jeff Probst had also revealed that for the first time since Survivor: All-Stars, Survivor: Philippines would feature a three-tribe configuration in which one returning castaway would be part of each tribe.