The Spanish Liga leaders host the Greek champions after a draining domestic clash against Atletico Madrid, with Luis Suarez scoring late on to gain a valuable 1-1 draw at the Wanda Metropolitano.
Ernesto Valverde's side sit top of Group D with six points after two games, including an impressive 3-0 demolition of Juventus.
However, there is enough quality in the group - with Sporting breathing down the necks of both Barca and Juve - for Olympiakos to blow things wide open with a shock result.
The match will be shown live on BT Sport Extra, with coverage from 19:30 BST for a 19:45 BST kick-off at Camp Nou, Barcelona.
BT Sport subscribers will be able to stream the match online via the video player and the BT Sport app.