Complex sentence: From 2011 to 2014 he drove for the Sauber Formula One team, but lost the drive at the end of the 2014 season, when he signed with Ferrari as test and reserve driver for 2015.
Split into simpler sentences: From 2011 to 2014, Gutiérrez drove for the Sauber Formula One team, but lost his drive at the end of the 2014 season. He then signed with Ferrari as their test and reserve driver for 2015.