The NRL's mid-season merry-go-round gathered momentum on Monday with controversial St George Illawarra pivot Richie Williams jumping ship to join Penrith.

Williams will have his first training run with the Panthers on Tuesday after being released by the Dragons and agreeing to a deal for the remainder of this season and 2008.

His switch comes just two days after playing for the Dragons in their 20-12 loss to Parramatta.

While Williams is seen as the logical replacement for the departing Peter Wallace - who is joining Brisbane next season - Penrith coach Matthew Elliott was adamant the 21-year-old could make an instant impact.

"Most certainly ... while we certainly want him to improve he won't be just being groomed for next year," Elliott said.

"He's a player that we think can come here and help us right away.

"Obviously with the loss of Peter Wallace next season it was a position that we were looking to bolster and Richie's a player that I've been a fan of for a couple of years."

Williams burst onto the scene with a try-scoring double on debut as the Dragons opened their season with a win over Gold Coast.

The effort was spoiled when Williams was criticised by Dragons coach Nathan Brown for gesturing to Titans fullback Preston Campbell as he went over for the match-winner.

Williams underlined his potential with another two tries in his third game before hitting the headlines again when a verbal spray aimed at Sydney Roosters pivot Braith Anasta backfired in spectacular fashion.

Anasta responded to jibes that he was past his best by leading the Roosters to their first win of the season - an 18-4 victory over the Dragons on Anzac Day.

Williams was subsequently dropped to Premier League but has been called back into the top grade over the past fortnight with the Dragons skipper Ben Hornby sidelined with a calf injury.

Asked if he was concerned about Williams' off-field behaviour, Elliott said:

"There's always concerns about that sort of stuff, not just with Richie but with all players and he's been made very aware of it by the Dragons and on the way here he's been made aware of it by myself.

"I had a really good chat to Richie and there's certainly no mistaking that he knows what the expectations are of him both off the field and on the field.

"Sometimes a change of environment is exactly what people need to bubble up - I think (new Dragons recruit) Jamie Soward's a good example of that."

The Panthers also announced the signing of 20-year-old Canberra halfback Josh McCrone on a two year deal.

McCrone had two years at the Raiders while Elliott was still in the nation's capital but has yet to have a taste of NRL football.

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