Reading pair Sean Morrison and Jordan Obita have both signed new contracts at the Madejski Stadium.
Ipswich defender Aaron Cresswell has signed a two-year extension to his contract.
Huddersfield are unlikely to conclude a permanent deal for striker Jermaine Beckford during the January transfer window, according to manager Simon Grayson.
Beckford joined the Terriers from Leicester at the end of September until the end of the year and Grayson has made no secret of his desire to extend his stay until the end of the current season.
The Huddersfield boss also revealed other deals are in the pipeline and did not rule out the club making a permanent signing when the transfer window opens.
He said: "There's a lot of work going on behind the scenes. One or two will stay and one or two will go back. We're concentrating on the football, but I think there are some postive talks with a couple of clubs who we are doing deals with at the moment.
"There's a possibility that we'll be bringing in players on loan and permanent signings. You've got to be realistic in your thoughts and transfer targets.
"Using Jermaine as an example. Will we be able to sign Jermaine on a permant basis? No. I don't think anybody in the Championship will be able to afford Jermaine's wages and transfer fee that Leicester will be looking for.
"So that one would be a loan deal until the end of the season and then we'll assess the situation then. Simon Church, if you're looking to do something with him, would be more realistic because he's got six months left on his (Reading) contract and Adam Hammill has been made available at Wolves, so that would be an easier option to do.
"I'm just going through the loan options, it doesn't mean to say we're going to carry through with these options, but I'm signalling how easy or hard a deal is to conclude."