Teams in the Barclays Premier League are set to receive a huge financial boost next season thanks to a new £3billion television deal and Clarke is believed to have asked for funds to strengthen his side.
West Brom are currently eighth in the overall league standings but Foster does not think radical changes are needed despite the cash injection.
"I'm curious about the summer and it's the same for the fans as well," Foster told the Daily Star. "The fans probably think we can bring 10 or 12 different players in with the new TV deal.
"There's going to be a lot more money being pumped into the Premier League next season but you don't want to go crazy.
"You don't want to add too many players because you might upset the good balance that we've got going at the minute.
"I'm sure the gaffer will be sensible and maybe add three, four or five faces."
Foster added: "West Brom have always been good at recruiting players that are good lads.
"We're a liked football club and that goes for everybody throughout the whole set-up, from the canteen staff right through the rest of the club.
"It's up to the manager whether or not he wants to add to the squad and, if he does, what sort of players he wants to bring in. I'm sure we'll roll with that because we trust him. The players we brought in earlier in the season have been good acquisitions."