Mariner will work under Manager Paul Sturrock at Plymouth, which is second from last in the Championship. He spent six seasons with the Revolution, joining Coach Steve Nicol's staff in the spring of 2004. During his tenure in New England, the Revolution advanced to three MLS Cup finals, four Eastern Conference championship games, and won the 2007 U.S. Open Cup and 2008 SuperLiga.
"I have had a wonderful experience with this club," Mariner said, "but I was presented with an offer that is very special to me personally, and I could not pass it up."
Mariner, who earned 35 international caps for England, started his professional career at Plymouth Argyle. He later played for Ipswich Town, Arsenal and Portsmouth.
Mariner coached in the APSL with the Albany Capitals and San Francisco Bay Blackhawks. Before joining the Revolution, Mariner was an assistant coach at Harvard University.