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.
Schalke say they have received no offers for Klaas-Jan Huntelaar and understand that Arsenal do not have the money to sign the Dutchman.
Huntelaar's contract with the Bundesliga side expires at the end of the season and he has been linked with a January switch to the Emirates Stadium.
However, Schalke insist they are confident of keeping the striker and have played down the chances of the Gunners being able to afford him.
"There have been no offers or any sign of Klaas-Jan leaving," general manager Horst Heldt said in The Sun.
"If someone comes to us six months before the expiry date, and has a lot of money, we will deal with it.
"But from Arsenal circles we hear there is no money anyway."