The Brit finished fourth in the Bahrain Grand Prix last weekend, but he has called on the team to "work hard" in the months ahead.
"We've got to take a great amount of credit and positives from the first four grands prix," the Scot told reporters at a press conference.
"But the team needs to work hard to bring updates because if they want this podium, they're going to have to work for it - probably more than we are at the moment.
"They want a podium. I said give me a faster car and they'll get a podium. If they work a bit harder in the design office and essentially get a bit more resource in there, there's no reason why we can't do it."