OWINGS MILLS, Md. -- A Baltimore Ravens player tested positive for the coronavirus, putting the team back in the NFL's intensive protocol.

The infected player is self-quarantining, and there were no other high-risk contacts, according to the team.

The Ravens announced they were informed of the positive test Thursday morning. Baltimore had just come off the intensive protocol on Wednesday, when All-Pro cornerback Marlon Humphrey was activated off the reserve/COVID-19 list after 10 days of quarantining.

During Sunday's 24-10 win in Indianapolis, the Ravens increased their precautionary measures. Ravens coach John Harbaugh said players wore masks on the sideline, in the locker room after the game and on the flight back to Baltimore.

"It's something that we take very seriously and we're working hard at," Harbaugh said Wednesday.

Humphrey became the first Ravens player to test positive during the regular season, when he announced on Nov. 2 that he had become infected. Seven Ravens players were identified as high-risk close contacts to Humphrey but all returned after quarantining for five days.

The Ravens play at the New England Patriots on Sunday night.