If Grenier's name is foreign to most, that's not a surprise. He has competed in only six Indy Lights races, finishing in the top five only once (in 2011 at Barber Motorsports Park).
Grenier, 21, competed in only one Indy Lights race last season, at Long Beach with Team Moore. His five starts in '11 came with O2 Racing Technology.
He won one Pro Mazda race in 2010.
Bourdais was signed last month replace Ganassi-bound Tony Kanaan. This week's test is Wednesday and Thursday. AutoWeek