Allen joins the Lions following three years at NYCFC, where he played under Lions coach Jason Kreis in 2015. The fullback started 42 of his 53 regular season appearances for NYCFC since 2015, scoring one goal and adding 11 assists. This season, Allen started 10 of his 15 regular season appearances, registering three assists. In 2016, Allen made a career-high 24 appearances and his six assists were tied for the most in the league by a defender. Allen also started both of NYCFC’s playoff games in 2016.
The New Jersey native was drafted by Chivas USA in the 2012 MLS Supplemental Draft and began his professional career with Skive IK in the Danish second division in 2013. Allen made 82 starts from 2008 to 2011 at Monmouth University, scoring seven goals and adding 23 assists.