Despite this, there looked to be significant upheaval at Williams for 1993. Alain Prost ended his year long sabbatical from competition following his 1991 firing by Scuderia Ferrari, and Williams was interested in bringing him in. At the same time Ayrton Senna’s contract with McLaren was ending, as was the team’s engine contract with Honda, and he had long expressed a desire to pilot one of the Williams machines. Patrese decided to leave the team in the midst of this, joining Michael Schumacher at Benetton. Prost would eventually come to terms, which would cost Williams a shot at Senna and the chance to retain the defending world champion. Mansell and Prost were teammates at Ferrari for a brief period and the Englishman had bad blood with him from their time together, so instead of returning to Williams for 1993 he chose instead to drive for Newman-Haas Racing in the CART Racing Series. Prost also had a longstanding rivalry with Senna dating back to their days as teammates at McLaren, so he had a provision negotiated into his contract that allowed him to have veto power over the driver of the second Williams. Despite Senna’s apparent willingness to drive a Williams while collecting no salary, Prost said he did not want to drive with Senna again. Instead, Damon Hill was promoted to take the second Williams ride and Senna returned to McLaren for a final season, driving a Ford-powered car. His teammate for the season was Michael Andretti, whose departure from CART created the vacancy Mansell filled at Newman-Haas.