Sam Hunt -- Marcus Mariota Will Make Nashville Dreams Turn into Reality (VIDEO)

California should call Marcus Mariota ... 'cause he's the man to end long droughts -- according to country music star and ex-QB Sam Hunt, who thinks Marcus is gonna make it rain for the Titans.

On the heels of Mariota becoming the first rookie QB to toss 4 TDs in his first start ... we got Sam -- a huge Titans fan -- and asked him about MM's historic debut.

Hunt played ball at Middle Tennessee State, and was invited to Chiefs camp ... which means his review carries a little more weight than a casual fan. So, is it too soon for Titans faithful to dream about their first postseason since 2008?

Check out the clip -- Sam seems as down with Mariota as every chick seems to be down with Sam ... which is very, very, down.