England's plans for the Champions Trophy could need a significant rethink over the next few days following their two heavy defeats against New Zealand amid growing concerns over the fitness of Stuart Broad and Steven Finn less than a week before their opening match of the tournament against Australia.

Broad and Finn have missed the first two ODIs against New Zealand with knee and shin problems respectively. They are due to undergo fitness tests on Monday, although a clearer picture of their chances of making the Champions Trophy may not be available until Tuesday when the England squad reconvenes at Trent Bridge.

Broad's knee problem was picked up on the final day of the Headingley Test when he took a caught-and-bowled off Brendon McCullum. Finn's shin soreness suggests a more stress-related problem after his early-season workload. It would be a major, and almost unworkable, gamble for England to enter the Champions Trophy with two of their strike bowlers under injury clouds. Teams can replace injured players, subject to ICC ratification, at any time but once a player is removed he can't return to the 15-man squad.

"They are both a concern," admitted Alastair Cook, "but five or six days is still quite a long way away. They've missed two games and been out for a while, so we'll see."

However, even in the worst-case scenario where England lose both bowlers, Cook did not believe it had to be terminal to their chances. "I think that would be doing a disservice to the other 13 guys in the squad," he said. "If you take two premier bowlers out of any side it will hurt and you might have to change the way you play."

Cook gave a strong indication that England would consider moving away from the current balance of six batsmen and five frontline bowlers for the final ODI against New Zealand at Trent Bridge on Wednesday. When Broad and Finn are fit they make a strong bowling line-up alongside James Anderson, Tim Bresnan and Graeme Swann, but Jade Dernbach and Chris Woakes have struggled to fill the breach. Dernbach went for 87 in 10 overs in the second game and Woakes, albeit having suffered a dropped catch for the second match running, went wicketless again and was used for only seven overs.

As far as options go, quick bowler Boyd Rankin is part of the squad for the New Zealand series. Ravi Bopara, who has been made available for Essex's YB40 match against Surrey on Monday, would provide an all-round option and James Tredwell another spin choice.

"It's been a tough couple of games," Cook said. "Clearly when you lose bowlers of the quality of Stuart and Finny it leaves a hole. It has the given the opportunity to guys to show us what they can do. We've learned a lot about these players and us as a side. It's obviously a concern; the standards we've played to here haven't been good enough.

"You do tend to look, after a couple of defeats, at the balance and make-up of your side. We certainly have options to go both ways… at this point I'm sure we'll look at different combinations because the ones we've used haven't worked in these two games."

While conceding the series loss - and by such convincing margins - has dealt a blow to preparations going into the Champions Trophy, Cook remained upbeat that his team will be able to turn their form around.

"It's frustrating because you always want to build momentum and build confidence but as you look at the tournament from now you realise it's two weeks of cricket and you have to play your best for two weeks," he said. "Whoever does that will win the tournament. This will be of little relevance when we get there, but in an ideal world we'd have won these games. Sometimes when you lose good things can come of it."

Andrew McGlashan is an assistant editor at ESPNcricinfo