Verlander as the main SP signing would be very risky but have huge upside too.
Considering we started last season with a staff of Ryu, Diesel, Zeuch, Matz and an unproven Ray and ended up with one if the better rotations in baseball despite Ryu being decidedly average I think I'd be ok starting the season with Berrios, Manoah, Ryu, Verlander, as the top 4 guys.