The 20-year-old arrived at Stamford Bridge from Lyon for £26million plus add-ons in January, but he was sent straight back on loan to the French side until the summer.
James was made Chelsea captain by Mauricio Pochettino ahead of the new season following the departure of Cesar Azpilicueta, but is currently sidelined with a hamstring injury suffered in training last month.
Gusto has featured heavily in James’s absence, starting three of the Blues’s first five matches across all competitions so far this term.
The France Under-21 international said: “We are all sad for Reece. We must not forget he is our captain. He is important for the squad and the club.
“Now I must use this opportunity to replace him in a good way and show that I can play. When you sign for a top club, you expect to be next to big names. I know I have the skills and quality and I’m here for it.
“It was a similar situation at Lyon. [Right-back Leo] Dubois was also the captain. So, it’s nothing new for me. I have always learned from these situations. It’s important to have this type of competition.”
Gusto added: “We are starting to have a good team with a good understanding and, of course, a very good manager. Now we need to get Chelsea back where it belongs.”