Ferrari has offered the new spec engines to Sauber and Haas racing. It is still unclear if Haas has made the decision to switch over to the new engine in time for Barcelona or if the Hass drivers intend on waiting to make the switch when the teams will have more time to transfer over to the new engine package. Toro Rosso F1 will remain on the 2015 engine as a result of their agreement with Ferrari.
Sauber has struggled financially in recent months and lacks the appropriate funding to properly implement the new engine package. Sauber is hoping that Nasr and Ericsson will be able to manage the performance of the 2016 package without having the much needed aero assistance. This is an attempt by Sauber to get on the championship scoreboard in the hopes of earning some much needed prize money.