Hey,
No need to write Groovy script for this, You can achieve using property transfer feature.
Do this it should help,
1. First add listAllPlayers and getAgeForPlayer to a test case and then insert property transfer step between the two requests.
2. Add a property called NameTransfer (as you like)
3. Select the source as listAllPlayers and property as response. Declare the xpath to capture the element from which you need data to be transferred.
4. Select the Traget as getAgeForPlayer and property as request. Declare the xpath to define the element to which you are transferring value.
See the screen shot enclosed for your reference,
Hope this helps,
thanks,
