No, they are not related. Greg Olsen has an older brother named Christian, a previous starter for Virginia after transferring from Notre Dame; he also lives in Chicago where he works as a freight broker.
Eric Christian Olsen was born in Eugene, Oregon on May 31, 1977. He is an actor, known for Not Another Te3n Movie (2001), NCIS: Los Angeles (2009) and The Thing (2011). Olsen has been married to Sarah Wright since June 23, 2024 and they have one child.
You can watch NCIS: Los Angeles every Tuesday 9/8c.