The 26-year-old, who spent last season at Portsmouth, was brought to the coaches attention by skipper Liam Perkins.
Both Perkins and Worrall played for Hampshire last season, with the latter helping them to the County Championship Shield crown back in 2016.
Raiders assistant coach Ben Coulson was pleased to complete another summer signing.
He said: "When Liam (Perkins) suggested we check Elliott (Worrall) out you trust the instincts of your players, so we went along to a couple of games and were impressed by what we saw.
"Elliott brings both physicality and size to the pack, which is something we've been looking to add to our squad going into the new season. We're looking forward to seeing him run out at Roundstone Lane."
Don't miss out on all the latest breaking news where you live.
Here are four ways you can be sure you'll be amongst the first to know what's going on.
1) Make our website your homepage
2) Like our Facebook page
3) Follow us on Twitter
4) Register with us by clicking on 'sign in' (top right corner). You can then receive our daily newsletter AND add your point of view to stories that you read here.
And do share with your family and friends - so they don't miss out!
Always the first with your local news.
Be part of it.