Rodriguez, who was capped by Roy Hodgson in the 2-0 friendly defeat against Chile, was close to making the final 23-man squad before suffering a cruciate ligament injury against Manchester City in April.
He will be watching from home as England face Italy in their first game on Saturday and is backing Hodgson's men to prevail in Manaus.
"I don't think there are any limits as to how far they can go," he said. "If you look at the squad, the manager, they are brilliant. There really are no limits and it's an exciting time for England.
"I didn't really expect anything in terms of a call-up and I'm a great believer in everything happening for a reason. I will be watching it in full support and wishing the boys do well and I'm sure they will."
Rodriguez's team-mates Luke Shaw and Adam Lallana are out in Brazil along with Rickie Lambert, who moved to Liverpool from Saints last week.
"I have spoken to them all and they are all enjoying it," he said. "They are working hard out there and it's great to watch and support them. Conditions are very hard and they have worked hard to acclimatise and to prepare."
The 24-year-old is working hard as he tries to get fit and return to action with Southampton.
"It's going really well," he added. "I'm hitting my targets and working hard. It has been kind of enjoyable so far so it's quite good. The first thing I can think of is to get back and have a season playing again, that first game is what I'm looking for.
"It's more about phases of what I need to hit before I move onto the next stage. It could be sooner or later than I think depending on how the rehab goes."