Mehl was a successful goalkeeper every step of the way, starting in high school at Thomas Johnson, then at Lebanon Valley College, and finishing in the professional Major Arena Soccer League with the Harrisburg Heat. In high school, Mehl was an all-conference selection in 2004 after helping the Patriots to a 14-3-1 season and county, division, and regional titles.

He was a four-year letter winner at LVC where he started 49 games and captained the 2008 team to the Middle Atlantic Conference Commonwealth title. He ranks in the Top 5 in four LVC goalkeeping categories: career wins, career saves, career shutouts, and lowest career goals against average. He started 22 matches during a four-year career with the Harrisburg Heat and was named Most Improved Player in 2014 by the Heat fans.