Grant was Pompey's football director before moving to Chelsea and Redknapp said: "I didn't know him when he first came here. He was given to me - or put on me, in a way - and I wasn't happy about it. I must be honest I could have walked away again.
"But I didn't. I met him, liked him and we became good friends. He's a nice guy and I discovered he wasn't here to take my job.
"I found him a great help and I felt he was always going to go to Chelsea in some capacity. That was the plan.
"He's really a good guy. He's quiet, not a personality like the previous manager (Jose Mourinho) but he's done a terrific job.
"Once they get John Terry, Frank Lampard, Michael Essien and Didier Drogba back the championship is still open for them. We'll be stronger, too, when our four African boys are back from the Nations Cup."