Holgate has a year to run on his Toffees deal and Wilder said: There's a group of players ... I think with the loans, we've had a mixed bag with them all season. Ben Brereton Diaz has been outstanding and Mason, at times, has been good.
"I always think it's difficult coming in in January to really get into a rhythm and obviously he didn't, because of his sending off. That put him back a little bit.
There have been other (loans) that have not been very successful, so he'll be on a list. He's contracted to Everton for another year, so there'll be a lot of talk and wheeling and dealing and a lot of moving parts. But attitude-wise Mason has been great, his experience in the dressing room and his voice has been loud and positive. So we'll just wait and see and see how that all materialises in the summer."