Humphrey quarantined for 10 days after testing positive and missed Sunday's 24-10 victory in Indianapolis.
He is the first Ravens player to test positive during the season and announced he was infected a day after Baltimore had lost to the Steelers.
His return will help a secondary that has been hit hard by injuries. On Tuesday, Khalil Dorsey (shoulder) became the fourth Baltimore cornerback to be placed on injured reserve. Humphrey has been the top playmaker on a defense that has allowed the fewest points this season. He is known for punching the ball away from receivers, which has led to four forced fumbles.
Last month, Humphrey became the NFL's second-highest-paid cornerback when he signed a five-year, $97.5 million extension, which included a $20 million signing bonus.