one-sided and boring over the course of the 2015 season than it had been the previous year. Red Bull's team principal Christian Horner called for the FIA to step in and apply rule changes that would level the competition, stating: "The FIA, within the rules, have an equalisation mechanism and that needs to be looked at." Red Bull subsequently threatened to leave the sport, should no measures be taken. While many commentators pointed out that Red Bull had enjoyed their own share of dominance in the prior years, Formula One supremo Bernie Ecclestone voiced understanding for the team, saying: "There is a rule that I think [former president] Max [Mosley] put in when he was there that in the event... that a particular team or engine supplier did something magic - which Mercedes have done - the FIA can level up things. They [Mercedes] have done a first class job which everybody acknowledges. We need to change things a little bit now and try to level things up a little bit." Mercedes' executive director Toto Wolff reacted to the calls by urging his rivals to "get your fucking head down and work to sort it out". McLaren driver Jenson Button also raised doubt over the practicality of rule changes, saying "There's nothing really to ban because it doesn't look like Mercedes are doing anything other teams aren't doing." Following criticism voiced by Red Bull, the future of engine supplier Renault was also a matter of debate. While Renault contemplated exiting the sport, another scenario that received media attention was a possible buy-out of the Toro Rosso team. The discussion about the future of the sport was additionally fuelled by the news that the German Grand Prix would be dropped from the 2015 calendar, due to a lack of financing. The exclusion of one of motorsport's most traditional events caused many to raise the question whether the same fate might await other traditional venues such as Monza. Fernando Alonso returned from his pre-season injury to take back his seat at McLaren, which had been filled by Kevin Magnussen at the previous race in Australia. Also returning was Williams driver Valtteri Bottas, who missed the previous race due to a back injury sustained during qualifying. Manor Marussia, who were able to field their cars for the first time in Malaysia, were under criticism after they failed to run their cars at the