Since Birk retired in February, the veteran lineman has passed another valuable commodity onto Flacco with the sale of his Baltimore County home to the Super Bowl Most Valuable Player quarterback for $1.385 million, according to records.
Flacco purchased the home from Birk earlier this year after the quarterback signed a $120.6 million contract that included a $29 million signing bonus and a total of $51 million in guaranteed money.
The modern single-family luxury home was built on just over one acre of land and includes a garage and fireplace.
Professional athletes in several sports, including the NFL, frequently sell real estate to each other due to familiarity and financial status.
A married father of six children, Birk now resides back in his home state of Minnesota. Along with former NFL defensive coordinator Ted Cottrell, Birk works as an appeals officer who handles NFL discipline cases.