Co-promoter Alex Harkess told the Edinburgh Evening News that the 30-year-old had verbally agreed to rejoin when the British speedway leagues resume in March – only to discover that Worrall has put pen to paper on a deal with one of their championship rivals.
Harkess admits it's a bitter blow to Monarchs’ team-building plans for the forthcoming season but insists they will look to recruit a rider of the same ilk, if not better.
“We would have liked to have kept Richie and we believed that he was wanting to come back,” he said. “But then all of a sudden we found out he's agreed to go elsewhere.
“He indicated for a long time he would come back next year and we weren't looking at anyone else because we believed that would be the case. He was very much in our plans. It's really disappointing.
“We didn't find out directly from him either, it was from other people. When I did manage to pin him down, he told me so we unfortunately had to agree that he wouldn't be coming back and that was that."
On a more positive note, Harkess remains hopeful Monarchs assets Sam Masters, Josh Pickering and Kye Thomson will be back in blue and gold next term.
He explained: "Everyone is going absolutely mad trying to sign riders just now. Normally we would hope to have our team done by Christmas, but in some years it's even been as late as February.
“We have spoken to the riders from last season’s team who we want to keep and are negotiating. But we don't tend to announce anything until the contract is signed and in our hands.
“That's how we’ve always done it and that’s what we’ll continue to do. We are certainly talking to people and trying to put it together.
“I understand that supporters get frustrated but, at the end of the day, we will put together the best team we possibly can.
“The average going up to 42 points is higher than it has been in the past so there’s a bit more leeway this time round.”
Harkess was reasonably satisfied with the season just finished – the club reaching the play-offs semi-finals and KO Cup final as the Poole Pirates claimed a league and cup double.
“We set out with the aim of making the play-offs and once you get there anything can happen,” Harkess said. “We managed to do that.
“At one time earlier on in the season I thought we were going to sail into the play-offs without any problems, but then Richie got hurt and we struggled at home dropping points. To be fair we did very well away.
“It was disappointing to go out in the semi-finals of the play-offs to Glasgow. I think a big thing was not being able to race them the night after we had beaten them in the KO Cup semi-final due to the weather because had we done, I think it would have been a different outcome as we had all the momentum.
“But Poole were worthy winners so we can have no complaints. They were the better team than us when it mattered.”