The trio, who missed the win over Northampton Saints last weekend, have been included in the starting line-up for the knockout stage and are joined by Ellis Genge as the only four changes to the starting side from the derby day victory.
The second row is unchanged, with Tomás Lavanini and Calum Green as the locks.
Ben Youngs, who made his 250th appearance for the club in the win over Saints, is joined by George Ford as the half-backs.
Charlie Clare, Facundo Gigena, Nephi Leatigaga are the front row cover, with back rowers Luke Wallace and Jordan Taufua the other forwards on the bench. Ben White, Zack Henry and Harry Potter are the backs included among the replacements.
Speaking about the French opponents ahead of the knockout fixture at Welford Road, the Tigers head coach said: “Castres are a very good side.”
“They have a well-balanced squad with a big forward pack, pace out wide, and half-backs who manage a game well, pushing for field position.
“This is a challenge we are all looking forward to at Leicester Tigers.”
Discussing the importance of the knockout fixture, Borthwick added: “Every game we at Leicester Tigers play is an important fixture.”
“I have said from the first day I arrived in Leicester that I expect any Tigers team to put in a performance that our supporters are proud of and that we put in an effort which supporters can see is up to our standards, whenever and whoever we play.
“This is our next game, therefore it is an important game.”
Leicester Tigers (v Castres Olympique, Welford Road, Sunday 3.00pm)
15 Freddie Steward
14 Kini Murimurivalu
13 Jaco Taute
12 Matt Scott
11 Nemani Nadolo
10 George Ford (vc)
9 Ben Youngs
1 Ellis Genge
2 Tom Youngs (c)
3 Dan Cole
4 Tomás Lavanini
5 Calum Green
6 Harry Wells
7 Tommy Reffell
8 Hanro Liebenberg
16 Charlie Clare
17 Facundo Gigena
18 Nephi Leatigaga
19 Jordan Taufua
20 Luke Wallace
21 Ben White
22 Zack Henry
23 Harry Potter
Castres Olympique: 15 Julien Dumora, 14 Geoffrey Palis, 13 Thomas Combezou, 12 Florian Vialelle, 11 Filipo Nakosi, 10 Benjamin Urdapilleta, 9 Rory Kockott (c); 1 Antoine Tichit, 2 Gaetan Barlot, 3 Matthew Tierney, 4 Ryno Pieterse, 5 Hans N'Kinsi, 6 Baptiste Delaporte, 7 Kevin Kornath, 8 Tyler Ardron.
Reps: 16 Pierre Colonna, 17 Julius Nostadt, 18 Wilfrid Hounkpatin, 19 Dorian Clerc, 20 Mathieu Babillot, 21 Maama Vaip ulu, 22 Bastien Guillemin, 23 Vilimoni Botitu