Mitchell's arrival at Redfern on Monday marked the end of a dramatic and drawn out contract negotiation that lasted three months.

And it ended in the 22-year-old becoming the latest to make the controversial switch between the two rival and foundation NRL clubs.

Robinson denied Mitchell's exit left a sour taste in his mouth.

"I had our time to together, we'd had our conversations, so Monday had no affect on me personally, to be honest," Robinson said on Friday.

"We knew where we were at and we knew our time had come to an end. I'm going to support Latrell for the rest of his career.

"What he delivered for us in his time here, not only a couple of premierships, but also an under-18s premiership. All of that time... that's not lost.

"We'll always remember that, but the time's up."

To Robinson, it mattered little that Mitchell went across Anzac Parade.

The incumbent Kangaroos centre, who will face his former club in round three, is expected so suit up at fullback under coach Wayne Bennett.

"I know there's a close rivalry and I love the fact that when those games come up, but, as I said, his time was up here," Robinson said.

"He was going to go somewhere, and we didn't have the choice over that.

"So you've just got to let it go."

Mitchell signed a one-year deal with the Rabbitohs with an option to extend in 2021 after the Roosters pulled their offer of a two-year extension worth around $800,000 per season in November.

It ended his time at the Roosters, which started in 2014 at SG Ball level.

Robinson said he regretted Mitchell's messy exit, but said their relationship as former coach and player is still strong.

The pair met a couple of times before Christmas.

"People want to be black and white about these things," Robinson said.

"It's disappointing for all of us the way it finished, we all would have liked it to be a lot cleaner, but our relationship is strong.

"When you go through those years like you have, it's not lost."

Australian Associated Press