Carroll made his first appearance in five months in Monday night's 2-0 win over Huddersfield Town after recovering from a hip injury.
The Englishman's return has brought into focus the role of Hernandez, who joined from Bayer Leverkusen in the summer and has scored twice in his first four league games.
Although many coaches seem to favour formations that make use of just one lone striker, Bilic believes that Carroll and Chicharito can play together.
"Definitely they can play together, they are complementary players," the Croatian told Sky Sports News. "That was the plan when we got Hernandez.
"We didn't buy him just because of that but also one of the reasons why he was great for us was because they are two players that can play with each other.
"The little and large striker, it's not that you don't see that in football anymore, a lot of teams play with two strikers. You have that maybe less nowadays but it's not old-fashioned. They can play together."
Up next for West Ham is Saturday's trip to The Hawthorns for a Premier League encounter with West Bromwich Albion.