England have suffered a blow ahead of their Euro 2012 qualifier with Montenegro after John Terry was ruled out with a back injury.Terry had been struggling in recent weeks with a rib problem, but now he appears to have picked up a fresh injury whilst with England.The Football Association has confirmed that Terry has returned to Chelsea for treatment and will not be involved at Wembley on Tuesday.The news is a huge blow to coach Fabio Capello, who has already lost Phil Jagielka from his original squad.Gary Cahill was called up to replace Jagielka, and he will now compete with Joleon Lescott to play in central defence alongside Rio Ferdinand as there will be no new call-ups at this time.Terry is the third player to withdraw from the initial squad after Aaron Lennon also pulled out to be replaced by Stewart Downing.Source: Skysports.com