Moore, a 6ft 7in forward, graduated from the University of Houston with a "double double" career average of 18 points and 10 rebounds. He has since played in Spain, Portugal, the Dominican Republic and for two teams in America's lesser pro leagues, the CBA and the USBL.
Moore replaces Bryan Williams, an early sacrifice to the Leopards' poor start, which never the less included an opening day victory at Newcastle, tomorrow's opponents.
The Leopards' coach, Billy Mims, said: "When you're two-and-three it's hard to be totally confident about any game. We still have a way to go."
Peter Knechtel has re-signed for Worthing Bears. He makes his second debut tonight at Leicester City Riders, who lost their seventh game out of eight by 90-81 at Manchester Giants in midweek.
Manchester's Tony Dorsey scored 34 points in the win, which lifted Giants into joint first place with Sheffield Sharks, the league's last remaining unbeaten team. Tomorrow they travel to Edinburgh Rocks, the only team without a win.