The Merseyside-born midfielder is a staunch Everton fan but joined Liverpool's academy aged six and motored through the Melwood system.
He seemed tipped for greatness when on his 15th birthday he made his debut for Liverpool Under-18s. Rossiter also played for the under-19 side at the same age.
But inside, he could not bear it and absolutely detested Liverpool due to his Everton fealty.
Karl Robinson, who has managed Oxford United, Charlton and MK Dons, was an academy coach at Liverpool when Rossiter was there.
"He [Rossiter] was a massive Everton fan so we had to ban him from wearing an Everton kit in the gym," Robinson said on the I Had Trials Once podcast.
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"But he hated Liverpool so much that he would just wear Celtic kit instead because he couldn't bear to put a Liverpool kit on.
"He refused to wear the Liverpool kit because he was such a big Everton fan and that isn't uncommon because so many players in the Liverpool academy who were local would've been Everton fans.
"I'm sure it would have been the same at Everton's academy where they would have had lads who were massive Liverpool fans."
Brendan Rodgers handed Rossiter his senior debut at Liverpool at the age of 17, which saw him score in a League Cup victory against Middlesbrough.
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But that following summer in 2016, the midfielder left Anfield after 13 years to join Rangers, where his first-team chances improved.
In total, he made five appearances for the Reds but has since moved to Bury, Fleetwood Town and now plays at Bristol Rovers.
"You've got to be honest with yourself," he said in 2020. "I was training under Klopp, but not really making an impact.
"The reality was that I wasn't going to be good enough to play every week at a huge club like Liverpool. Look at the names I was up against.
"The bar was set so high. We're talking top pros. There's no point kidding yourself. They were on a different level.
"I knew I needed to drop down a level or two. I thought I'd have a better chance of playing regularly at Rangers."