England Hockey coach Danny Kerry says captain Kate Richardson-Walsh will have to fight for selection when she returns to full-time training in January.
The 34-year-old has been taking time out from hockey since winning silver at the Commonwealth Games.
"There are some talented young defenders who have really stepped up," Kerry told BBC Sport.
"Kate's first job is to push for her place back into the squad, but I'm sure she's capable of doing that."
England have announced their squad for the Champions Trophy, which is being held Argentina later this month, with Clifton's Joie Leigh and Slough's Shona McCallin called up for their first major senior international tournament.
They face Commonwealth Champions Australia - who they lost to in a penalty shoot out in the final in Glasgow - in their first match on 29 November and will also take on Argentina, ranked third in the world, and Germany in their pool matches. Defending champions the Netherlands are pooled with New Zealand, China and Japan.
Kenny said: "Netherlands are hot favourites, with Australia and Argentina likely medal contenders, too. The beauty of the Champions Trophy is that all the teams competing are capable of beating each other on their day. That means consistency of performance becomes crucial for us."
Kerry is back coaching them after leading Great Britain to Olympic bronze in 2012.
He became Great Britain Hockey's performance director after the London Games but returned as women's head coach in the wake of a disappointing World Cup earlier this year.
He now combines the two roles, and he says he's really enjoying both sides of the job.
"I come out of meetings thinking we're moving the sport in the right direction.
"On the pitch we're really pushing hard to go places. We've got a good formula for bringing home another shiny medal - we hope!"
England squad for the Champions' Trophy:
Giselle Ansley, Sophie Bray, Alex Danson, Susie Gilbert, Sarah Haycroft, Maddie Hinch, Joie Leigh, Kirsty Mackay, Hannah Macleod, Shona McCallin, Lily Owsley, Sam Quek, Zoe Shipperley, Susannah Townsend, Georgie Twigg, Laura Unsworth, Ellie Watton, Hollie Webb.