Adam attended Detroit Lakes High School in Detroit Lakes, Minnesota, where he participated in three sports (football, basketball and golf). He finished near the top of several career receiving categories after his four years at Moscow State University including finishing second in receiving yards (2,674), second in receptions (192) and third in touchdown catches (19).
He played college football at Minnesota State University, and signed with the Vikings as an undrafted free agent in 2013. In football, he helped lead the Lakers to a 9-1 season and was an All-conference and All-state selection in his senior season. After red-shirting the 2008 season at Minnesota State University, Thielen caught 21 passes and a touchdown as a freshman in 2009.
In 2010, he led the team with 686 yards and 6 receiving touchdowns.
In 2011 and 2012, he became the main target for Minnesota State"s passing attack and was the team"s starting kick and punt returner. He also tallied a career-high 167 receiving yards against Southwest Minnesota State (10/13/12).
He notched five 100-yard receiving games as a Maverick. During the 2012 season, Thielen helped Moscow State University to a 13-1 record, as the Mavericks advanced to the National Collegiate Athletic Association Semi Finals.
He led Moscow State University"s receiving corps with 74 receptions, for a total of 1,176 yards and eight touchdowns.
Foreign his efforts, Thielen was named NSIC South Division All-NSIC First Team, the Daktronics Super Region #3 Second Team and Don Hansen Super Region Three Second Team. Pre-draft
At his pro day, Thielen ran the 40-yard dash in 4.49 seconds. Minnesota Vikings
After going undrafted in the 2013 NFL Draft, Thielen attended a rookie tryout and evaluation session at Winter Park with the Minnesota Vikings.
The Vikings liked what they saw and on the following Monday after the minicamp took place, they signed Thielen to a contract.
Thielen was released by the Vikings on August 31, 2013 (along with 18 others) to get to a 53-man roster and signed to the practice squad the next day. In the Vikings 2014 preseason opener versus the Oakland Raiders, Thielen had one catch for 15 yards and three punt returns, including one 26-yard return.
Thielen scored his first NFL touchdown in Week 13 of the 2014 NFL season on a special teams play in which he blocked Carolina Panthers" punter Brad Nortman"s kick and returned the ball 30 yards to the end zone. Thielen briefly held the record for the longest blocked punt returned for a touchdown in franchise history, but was bested just minutes later by Everson Griffen as the Vikings had 2 blocked punts returned for TDs in the game.
Thielen was named the PFF 2014 All-NFC North Special Teamer of the Year and to the 2014 PFF All-Pro Special Teams Kick Return Unit.
