England manager Gareth Southgate admits a selection headache has disappeared this winter.
Southgate spoke about how he's relieved that Jordan Henderson is back in Europe.
The former Liverpool captain was playing in Saudi Arabia during the first half of the season.
"It's easier to assess someone playing in a European league," Southgate said of veteran Henderson to reporters.
"For Jordan, I think he'll be excited about the game the other night - a derby atmosphere, playing in a game where firstly the club are absolutely delighted to have him there. He's had a really warm welcome and been really well received, and I'm sure that will mean a lot to him.
"I think Mainoo is doing brilliantly for a young player. He's had an excellent start for Manchester United. I'm not certain he's necessarily going to be a defensive midfielder, as such. He's quite a progressive player, but he's had a fabulous start to his career and it will be good to monitor him as we go forward."