MELBOURNE, March 4 (Reuters) - The New South Wales Waratahs' preparations for their Super Rugby clash against the Lions on Saturday have been thrown into disarray with late injuries to Wallabies scrumhalf Nick Phipps and lock Will Skelton. Phipps rolled his ankle in training ahead of the match in Johannesburg, while Skelton, who was among the Waratahs' best in their tight win over Western Force in last week's season-opener, had suffered a minor hamstring strain, the Sydney club said. The Waratahs were unconvincing in the scrappy 19-13 home win over Perth-faced Force and the loss of the Wallabies pair is a hammer blow to the 2014 champions' hopes of upsetting last year's runnersup at Ellis Park. The injured duo are also a doubt for the second match of their South Africa tour against the Sharks in Durban next week. Matt Lucas will start at scrumhalf and Senio Toleafoa at lock, with Jake Gordon and Maclean Jones moving onto the bench. "We have three Super Rugby quality half backs to choose from and Matt (Lucas) has the experience in that starting position," coach Daryl Gibson said. "Toleafoa has been preparing well with the squad and he comes off a strong 2016 season with the NRC (National Rugby Championship). "It’s now their time to step up and have a crack." (Reporting by Ian Ransom; Editing by Peter Rutherford)