NSW Waratahs are the visitors as Rebels coach Tony McGahan has named an unchanged starting line-up for the first time in 27 games and an extended bench, with one player to be omitted, for the fifth round of the 2017 Super Rugby season.
The 31-year-old Day is one of four changes made to the nine-player bench as the Rebels seek their first victory of the campaign.
“The starting line-up showed character and fight against the Chiefs last week so they’re all deserving of the opportunity to get another crack from kick-off,” McGahan said.
“It’s great that we can include some experience for Friday night’s game against the Waratahs with Lopeti Timani and Dom to provide some much-needed depth and quality from the bench when called upon.”
Day made 92 appearances for the Scarlets before he joined Bath in 2012 where he played 110 games in the England Premiership. Last season he played in Japan’s Top League with Toyota Verblitz in 2016.
Capped three times for Wales, he made his Wales debut against Ireland in 2015 and featured for Warren Gatland’s team at the Rugby World Cup.