Sidwell quit the Royals for Chelsea over the summer and Hutchings told the Wigan Observer: "I'm surprised to see Reading down there, but the second season at this level is always the hardest, as we found out.
"He was a big influence from them in midfield and you can lose momentum when you lose a key player like that.
"They've just had the one win, so they will be desperate to try to put that right against us. It will be a test of Reading's character how they perform after some indifferent results, and we've got to make sure we are ready for that.
"We will have to be on our guard, and we'll have to play a lot better than we did against Fulham if we are going to get anything."