Career
Collegiate
Mattern played collegiate soccer at the University of South Carolina where she was a two-time All-American in addition to being a Freshman All-American. In 2009, she was a consensus first team selection after earning All-America nods by the NSCAA, Soccer America and the Lowe"s Senior CLASS Organization. In her final season, she was captain of a defense that was ranked Number.
9 in the nation and led the Securities and Exchange Commission in every defensive category en route to 15 shutouts and a berth in the National Collegiate Athletic Association Round of 16.
Club
Mattern was selected by Atlanta Beat as the first choice of the third round and 21st overall selection in the 2010 WPS Draft. She was the Beat"s second pick and the fourth defender overall selected in the WPS Draft.
In late 2010 she joined the Charlotte Lady Eagles. In the summer of 2011 Mattern joined Football Club Twente together with Danielle de Seriere.
With Ashley Nick the Dutch club already had an American player.
Due to an injury Mattern missed the first couple of matches. Since 2013 she has played for the Carolina Elite Cobras in the United States and for Mallbackens IF in Sweden.