Cattermole was back in action in the goalless Premier League draw at home to West Brom last weekend, following two months on the sidelines with a groin problem.
"Lee is contagious – he brings something that is very rare and no other player in the team has got," Poyet told the club's official website.
"He also helps the supporters a lot because they love him to pieces and that helps the atmosphere and everybody around him.
"I'm pleased he is back and I'm pleased he got through the game [against West Brom] without any problems other than being very, very tired.
"He is also happy to be back so it is perfect now."
Sunderland visit Manchester United on Saturday.
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