I can imagine 2 Hammer Bros. just sitting around, gettin' lazy. And Mario appears. Here's how it'll go.
Hammer Bro 1: Hey, dude. Look. It's Mario. Should we hammer his butt to the ground?
Hammer Bro 2: Nah, we can wait a while.
Mario: Um, can you 2 hurry up and start running around jumping and throwing hammers? I have a Tanook/Tanuki Suit waiting for me.
Hammer Bro 1: No way, man. We're on shrooms...
Hammer Bro 2: Yeah, besides, we're livin' up to our name already. So don't think about throwin' out our good stuff, man.
Mario: Shrooms? You mean the ones I use?
Hammer Bro 1: Naw, the ones that make us HIGH, man.
Hammer Bro 2: Whoa..I figured something out.
Hammer Bro 1: What?
Hammer Bro 2: We're Hammer Bros, right?
Hammer Bro 1: Yeah. And?
Hammer Bro 2: We're supposed to be hammering Mario, as in throwing hammers at him. Right?
Hammer Bro 1: Right. So?
Hammer Bro 2: Instead, WE'RE the ones being hammered! I mean literally. We're SOOOO hammered right now.
Hammer Bro 1: Ooooh. I see. We're just too hammered to fight. Sorry, Mario. Looks like you'll have to find someone else to fight.
Mario: No way! I'm fighting you, and you'll like it! *jumps on the Hammer Bros. and receives Tanooki/Tanuki Suit* Mama mia, what does Bowser have these guys on, anyways? *returns to map*