Chelsea captain John Terry fears Manchester United's re-signing of striker Wayne Rooney will kickstart their season.
The Blues central defender is worried that now things are sorted, Sir Alex Ferguson's men will begin to push their way up the table and become a genuine title threat as Chelsea attempt to defend last season's Premiership.
"I think Wayne staying will boost them and make it harder for us," he said.
"On the back of what has happened United will probably go and spend in January and at the end of the season.
"The fact that clubs haven't been buying because of what's happened financially in the world has maybe helped Chelsea in the last few years. Wazza staying is massive for them."
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