Here’s why Pepe Replaces Casemiro?

Different Positions: Their playing styles and strengths differ significantly. Casemiro is known for his defensive abilities, tackling, and controlling the midfield, while Pepe excels on the wing with his pace and attacking skills.
Squad Depth: It’s more likely that Pepe was brought into the squad to provide depth due to Casemiro’s absence, rather than being a direct replacement for his position. The manager might shift other players around or use a different formation to compensate for Casemiro’s defensive presence.
It’s difficult to say for sure why Pepe was selected without knowing the coach’s specific strategy. There’s a chance the manager might:

Adapt Tactics: Adjust the team’s playing style to address the absence of a defensive midfielder.
Use a Different Midfielder: Pick another midfielder with a skillset more suited to filling Casemiro’s role.
For a more like-for-like replacement in Casemiro’s absence, the coach would likely select a central midfielder known for their defensive capabilities.