The Baggies boss says the club will look to extend the striker's deal following reported interest from elsewhere, and insists his success this season is no surprise
The 20-year-old - whose contract is set to expire at the end of the season - has caught the eye with five goals in seven appearances in all competitions this term, including strikes against Manchester United and Arsenal.
It will revealed recently that Saido earns £850 a week - a comparatively small sum for a Premier League footballer - reportedly prompting interest from elsewhere, but Clarke insists the striker will remain at the Hawthorns this season.
"It's just speculation and the speculation is rubbish," he told reporters at the Asian Football Awards. "He's under contract with West Brom until the end of next season, so we've got plenty of time to sort out Saido's future.
"He's a sensible boy. He understands that all the rewards and riches come with hard work and he has to just concentrate on his football and let other people worry about his contract situation and whatever.
"Saido has got a big future in the game and all he can do now is work hard and make sure he is still a top player in 10 years' time."
Clarke went on to say that he has not been caught off guard by the success Berahino has enjoyed this season after monitoring his progress since his appointment as manager last year.
"It's no big surprise with Saido," he added. "He trained with the first team in pre-season last year then went on loan in the Championship to get to some good experience at Peterborough.
"Unfortunately he picked up a bad injury and he was out for seven months, but he's had another great pre-season with us and has forced his way into the first-team reckoning."