After watching his side open their Premier League season with a 1-0 defeat to Southampton on Saturday, the Scot suggested that he could yet dip further into the market to strengthen before the September 2 deadline.
The Premier League club completed a season-long loan deal for Matej Vydra from Udinese last week, with the striker joining fellow signings Nicolas Anelka and defender Diego Lugano.
However, following a last-minute penalty from England striker Rickie Lambert that gave Southampton the points at The Hawthorns, Clarke revealed there may be room for more business - although he did see enough to suggest that West Brom can hold their own this term.
"I think every manager will say that they want to strengthen," he said. "I think we showed enough today to show that we’re going to be competitive again in the Premier League.
"The big decision went against us."
Lambert's spot-kick - which came after Youssouf Mulumbu had fouled Luke Shaw - ultimately meant that West Brom were made to pay for failing to take their chances in the game.
Clarke, though, still took heart from a battling performance.
"I thought Southampton defended really well," he added. "We created two or three really good opportunities in the second half.
"(Southampton goalkeeper Artur) Boruc made an unbelievable save at the end.
"James Morrison looked like he had a goal and the defender managed to block it on the six-yard line, so we will create chances, but it wasn’t our day."