McDermott, who enjoyed a loan spell at Chesterfield earlier this season, told the Scunthorpe Telegraph: "While I was out on loan at Chesterfield in League Two earlier in the season I was playing fairly regularly.
"It's a lot harder in the Championship. It's a level I have not played at before. It takes some getting used to.
"There is also a lot more competition for places. That's what I want though, I want to be challenged, I didn't want it to be easy for me coming here."