Is Ethernet even possible using the SAME53J ?

Hi,
 
I didn't know where to ask this question, so this seemed like the best spot.
 
In the datasheet http://ww1.microchip.com/downloads/en/DeviceDoc/SAM-D5xE5x-Family-Datasheet-01507B.pdf :
 
"Table 1-1. SAM E53/E54 Family Features with Ethernet" of says that there is a set of 64 pin parts, the SAME53J series, which have Ethernet controllers. But, when you dig into "Table 6-1. Multiplexed Peripheral Signals" , the signal GRXDV is only available in parts with 100 pins or more. GRXDV does not appear to be available on the 64 pin part.
 
How can the Ethernet data interface even work without the receive data valid signal?
 
Thanks,
 
Hedley