The former Liverpool striker returned to Pompey yesterday and admitted: "I have played with Jermain a few times at under-21 and international level and we have got a good record together.
"We know each other's games inside out and if we play together we will click straight away.
"We have got a few England players in the side and it is good to have international players playing regularly together.
"But there is no guarantee and I have to earn my place, but it is something I look forward to.
Delighted Pompey boss Redknapp added: "They (Crouch and Defoe) finished up playing in the last international and it is a good prospect, having a big 'un and little 'un.
"I am delighted to have him back here because I think he is a terrific player. I never expected to see him back again.
"People always talk about him being tall but he has got great feet - you only have to see some of the goals he scored last season.
"He is not in the England squad for nothing. He went to Liverpool and did well and established himself in the England team and proved he is a top player."
Crouch left Pompey in March 2002 after scoring 19 goals in 39 games when they were a struggling second tier outfit with little obvious chance of achieving top-flight status.
His £5million departure helped fund the following season's promotion to the Premier League and since then they have gone from strength to strength, culminating in last season's FA Cup win.
Crouch, who also played under Redknapp for Southampton in 2004/05, continued: "They have built a good side and there have been big changes, the club is unrecognisable from the last time I was here. It is a very strong side and we can compete against anyone.
"Walking through the doors brought back a lot of great memories but as a side and a squad it has certainly improved and we have got a chance to progress even more."