Former Newcastle midfielder Guthrie, who spent the latter part of the 2014/15 season on loan at Reading, is joined on the way out of the Madejski Stadium by Zat Knight, Yakubu, Jure Travner and rookie goalkeeper Mikkel Andersen.
The Royals, who reached the FA Cup semi-finals but at the expense of their Sky Bet Championship form, have offered contracts to Adam Federici, Alex Pearce, Jem Karacan and Stephen Kelly and discussions are on-going.
A club statement read: “As we enter our third year out of the Premier League, the club’s owners recognise the need for Steve Clarke to freshen his squad ahead of the new campaign, and this is the beginning of that process.
“After a period of financial instability and with the Financial Fair Play regulations in place, the owners are also making a concerted effort to get back to the sensible wage principles that have long been the club’s trademark.
“Striking the right balance will be key to a sustainable model for success.”