You've got to move on," he said today. "In the last two Olympic cycles we lost players. We've got some good young talent and that's exciting and they're really keen to be there."
McCaw, 27, has won 246 caps. Hager admired her perspective after having a chat today.
"She said if she can't give 100 percent then she can't commit properly. It takes a lot of courage to do that.
"The others, I feel, are at the same stage in their lives. You enjoy playing but it's the hard yards, all the training, getting back into that again. That's the hard bit.
They have all moved on with their lives, and as Gemma said you've got to be 100 percent committed. Doing it half hearted doesn't do you or your team any service," Hager said.
In naming his Oceania Cup squad, Hager singled out young North Harbour defender Steph Dickins and midfielder Tarryn Davey from the national league winners Midlands, for special praise. Both have won only seven caps but caught the eye at the tournament last week.
"Steph is a very fit, strong girl who offers a bit out of the back and Tarryn was very good in midfield and her conditioning at speed is very good."
Eight of the national league-winning Midlands team are in, along with three from runnersup Northland.
Midlands' Rose Keddell returns after getting injured at the world league tournament in Belgium this year, while four players have dropped out from that Belgian squad - midfielders Pippa Hayward, Jordan Grant and Erin Goad and attacker Kirsten Pearce.
The sixth-ranked Black Sticks have this week off before preparing for Sydney, where they will face world No 5 Australia and lightweights Papua New Guinea from October 11-15.
New Zealand squad for the Oceania Cup:
Goalkeepers: Sally Rutherford (Midlands), Grace O'Hanlon (Auckland)
Defenders: Sam Charlton, Rose Keddell, Frances Davies, Natasha Fitzsimons (Midlands), Ella Gunson, Stacey Michelsen, Brooke Neal (Northland), Liz Thompson (Auckland), Stephanie Dickins (North Harbour)
Midfielders: Tarryn Davey, Shiloh Gloyn, Amy Robinson (Midlands), Kelsey Smith (Capital)
Strikers: Olivia Merry, Rachel McCann (Canterbury), Sam Harrison (Auckland)