Kammala wannan jumla: An ba Walker cikakken wurin zama na Formula One don tuka Lotus 72 a kakar 1972, a matsayin mai lamba biyu ga Emerson Fittipaldi. Yayin da kakar wasa ta ci gaba, duk da haka, duka Walker da ƙungiyar sun zama masu ɓacin rai. Bayan Lotus gano Walker ya gwada wani Formula biyu mota ga wani tawagar, ya aka sauke daga tawagar ga
GP na Italiya da GP na Kanada, inda aka maye gurbinsa da Reine Wisell. Walker ya dawo ne domin gasar US GP, amma ya yi ritaya.