The Blues lead the tie 2-0 after Kai Havertz’s early strike and an own goal by Ben Davies gave Chelsea FC the victory in the first match.
The duo tested positive last week and missed the 2-0 first-leg victory over Spurs as well as the FA Cup win over Chesterfield.
Chelsea thrashed Chesterfield 5-1 in the FA Cup fixture at Stamford Bridge on Saturday.
He recently passed 450 Blues appearances and started his 300th Premier League game in the draw with Brighton last week.
With more injuries and positive Covid tests in his squad, Tuchel had to make six changes to his team from the side which drew with Liverpool at the weekend.
He was playing on the right side of midfield in the first half and was pushed slightly further upfield in a front three after the break.
Tuchel has stated that Lukaku was always the club's number one choice during their pursuit of a striker last summer.
The Brazilian defender has put pen to a new deal that will keep him with the Champions League winners until the end of the 2022-23 season.
The manager also confirmed that the Belgian striker is in contention to return for the Blues in Wednesday's Carabao Cup game.
Liverpool lead the Premier League battle against Chelsea 2-0 in the early stages, but Mateo Kovacic and Christian Pulisic leveled the scoreline.