The Liverpool star believes the emergence of Parker as an England regular has strengthened Capello's options and is convinced that Wilshere can come back strongly.
"I haven't been part of the squad recently, but speaking to the lads, it seems the atmosphere is good, the spirit is good and they've qualified so it's something to look forward to," he told the Mirror.
"But we're at that stage now where people get carried away, expectations go through the roof when it's important to stay grounded and focus on the important challenges ahead.
"The competition is healthy in the England squad. There's three or four more friendlies before the tournament and hopefully that can help bring the best out of the team performance.
"But I think the priority is to get in the squad and then show the manager that you're worthy of a place in the starting 11. I think that's the aim for all of the players at the moment.
"Scott has done fantastic. I think he's used the disappointment of not getting into squads in the past to really drive him on and improve his game.
"I think that's showing in his performances. He's probably one of England's most consistent players over the course of qualification and certainly deserves his place in the team.
"Everyone wants to see Jack back as quickly as possible. He's such a talented kid and I'm sure if he gets back to the form he was showing previously then I'm sure he'll be a dead cert to get into the 23.
"He's a fantastic talent. I don't know how much longer the injury will take to heal, but anyone wanting England to do well wants to see him back.
"I want to see him playing really well again because he's a great player to watch. Us as England players want him to be involved again and to help make us stronger."