Rosenior, who was sacked on Wednesday afternoon, oversaw a disappointing run of five straight Premier League defeats without scoring that led to his departure.
The club’s dire form has seen them slip down to eighth in the Premier League table and seven points behind fifth-placed Liverpool in the final Champions League qualification spot.
As Rosenior steps down, Under-21s coach McFarlane will take charge until the end of the season as he handles the final 5 games in search of European football.
McFarlane was placed in caretaker charge of the first team after Enzo Maresca’s departure in January and presided over a 1-1 draw away to Manchester City as well as a 2-1 defeat to Fulham.
Terry, who has been working with the club’s academy, spoke on his return to the first team as he backed the 40 year old who continues to get Premier League experience.
“I am not sure what Calum’s backroom staff is going to look like, I have not had a call, I have not had a message,” said Terry on Wednesday night. “I will be continuing my role in the academy, I will be in the academy tomorrow, a big couple of games coming up.
“We will all get behind Calum, he did a great job away against Man City previously and we will get behind the boys because that is what we do.”
Starting with Sunday’s FA Cup semi-final with Leeds United, McFarlane’s Chelsea return won’t be easy as he aims to do what Rosenior found almost impossible and win this weekend.