No. For PoE you need a PoE controller and then you need a MAC and PHY to convert the ethernet twisted pair signals into something the microcontroller can read (PHY decodes the signal for the MAC which handles packets and etc)
You can theoretically use something like [1] or [2] to connect the SPI bus to an ethernet controller.
You can theoretically use something like [1] or [2] to connect the SPI bus to an ethernet controller.
[1] http://www.mouser.com/new/wiznet/wiznetW5200/
[2] http://www.asix.com.tw/products.php?op=pItemdetail&PItemID=1...