The Scot is concerned by Hull's lack of creativity.
As a result, some sections of the home support responded to the performance by booing the players, with City winning just one of their last five league outings.
Worryingly, Hull have only found the net twice in those five matches, and although defender Robertson admits that it is indeed a concern, the Scot is adamant that his team-mates will rediscover their free-scoring form shortly.
"We need more movement all over the pitch. We're not creating enough space or picking the passes," he is quoted as saying by the Hull Daily Mail.
"That's a worry but it's something that will come. We've got some excellent footballers in there. We're going through a bad spell at the minute but I've no doubts we'll pick ourselves up."
Robertson is perhaps vindicated in his concern. It is a terrible time for Hull to hit a rough patch, but there is still plenty of time in which to break back into the top two.
It is also worth pointing out that it is in their own hands. Bruce and co sit two points behind second-placed Middlesbrough with a game in hand.