Rovers completed a youth loan deal to bring the highly-rated defender from Manchester City until the end of the season on Friday with the boss predicting big things for the Dutch youth international.
Rekik is expected to go straight into the squad for Saturday's FA Cup tie with Arsenal at the Emirates with Appleton delighted to have him.
"I'm delighted to bring him here," said the Rovers boss. "He is a young player who I have worked with before at Portsmouth. We took him on loan there last season.
"He's 18 years of age, a Dutch youth international and has great experience in terms of the football club he's playing at in Manchester City.
"He played against Reading earlier on in the season, he's been on the bench in the last couple of months, he's a player who can play left-sided centre half or left-back, so he can provide us sufficient cover in those areas.
"The boy is full of quality. I'll put my neck on the line and say that the boy will be a Premier League player for many years. City are very lucky and I feel lucky that we are able to bring him in for the short-term.
"Hopefully we can use him to the full extent. I'm sure he'll be a great asset and hopefully push us towards what hopefully would be a great end to the season."