He played college football at Marshall University from 2005 to 2009, and was signed by the Baltimore Ravens as an undrafted free agent after the 2010 NFL draft.

A native of Lakeland, Florida, McClellan attended Kathleen High School, where he was rated as a two-star recruit by Rivals.com.

McClellan played as the fourth string middle linebacker (Behind Ray Lewis, Jameel McClain, and Dannell Ellerbe).

With an injury to Terrell Suggs and the departure of Jarret Johnson to free agency in 2012, McClellan had a chance to compete for a starting outside linebacker spot with Paul Kruger, Courtney Upshaw, and Sergio Kindle.

In the divisional round of the playoffs against the Los Angeles Chargers, McClellan recovered a fumble off a muffed punt.