England will not play Graeme Swann in the Champions Trophy if it puts his Ashes participation at risk.
England are two wins from winning an ICC 50-over tournament for the first time after 38 years of failure.
But Swann, their leading spin bowler, is struggling with a calf problem and England have a tricky evaluation to make on whether he should play in the semi-finals and final if they make it.
Swann is fully recovered from his winter elbow surgery, but he has missed three of England's last four one-day internationals, first because of a sore back and now his calf.
Cook said that Kent captain James Tredwell is a more-than-useful replacement if they decide to rest Swann ahead of this summer's main event, the Ashes.
Play it safe
"James has done a fantastic job, and we are lucky in that department to have two outstanding bowlers," Cook said.
"Tredders is almost unlucky in one way that Swanny has been ahead of him.
"Obviously, we are going to play it safe with Swanny. He has a tight calf, and it just depends how he pulls up over the next couple of days.
"He will not be risked, because we are fortunate enough to have Tredders - and he is more than just a back-up."