Lakeside Hammers heat leader Peter Ljung will not be returning to the club for the 2012 Elite League campaign.
The 29-year-old, who averaged 5.55 points last season, has decided he cannot commit to the Hammers after being handed a Grand Prix berth.
The Swede has already secured a ride with Polish and Swedish teams.
"Peter has achieved his GP ambition and quite rightly, in my opinion, he wants to plan around it," Hammers boss Jon Cook told the club website.
"He would have been a rider we would have liked to include but that will have to wait for future seasons.
"He was very genuine in his positive feelings to all at the club and his wish is to return at some time in the future."