Back in 2017, the pair were teammates at Brighton and played together for the reserve team.
"I remember training with Rob and coaching him – we knew what his potential was," Rosenior explained.
"I said to him when I came in, I'm so proud of him, to be at this club, to see how his career has progressed, off the pitch as well. He's got two children. I saw Rob when he was 17 years old; he was a kid, talking about when he passed his driving test, so to see his progression is great.
"I've got a great connection with him. The scary thing with Rob is that I know how much he can improve as well. He's already playing at a really high level."
He also said: "You should always play to a player's strengths, whether it is the goalkeeper or your number nine. You want them to be comfortable and play the way that they're comfortable. Rob's already shown me fantastic things, especially his distribution against Brentford, which was outstanding.
"There were a couple of long passes to Pedro Neto where we nearly scored from, but you always want to improve every player as well."