Interpretation 1: A nickname for Cardinals is Cards. Cards also refers to standard playing cards. The best hand in poker is a royal flush. Additionally, “in the cards” refers to something determined ahead of time. Thus, this man is equating the on-field success of the Cardinals as being a foregone conclusion, and that their success will resemble that of a royal flush, while craftily inserting a Cards/cards pun.
Assessment: Unlikely to be the sign-maker’s intended meaning. Too simple. Do you see that man’s face? There’s something going on in that man’s mind–his twisted little mind. Yeah. He’s up to something. He’s up to shenanigans. And hey, shouldn’t those be tarot cards? Isn’t that what “in the cards” really means? Maybe he’s concealing the fact that he’s a witch doctor or shaman? He is no ordinary man. That is no ordinary sign.
Interpretation 2: The man is trying to tell the St. Louis Cardinals that World Series rings are literally hidden within the cards displayed on his sign. They are free for the taking, so we can all stop playing baseball and just skip right to handing out rings. He would like representatives of the Cardinals organization to contact him about retrieving the rings post haste, so as to avoid the nonsensical time-waste of on-field competition. Someone could injure themselves, ya know? Or, god-forbid, say a naughty word.
Assessment: Somewhat likely. However, given the straight-on camera angle it’s difficult to tell if the sign contains ring-vaults hidden behind the sign large enough to contain ~100 rings each*. This seems to be a requirement of the above interpretation. Also, unless the man is particularly strong, it’s unlikely he could so effortless lift and grasp a sign weighing as much as however much ~500 rings weigh (about 80 lbs?). But but he is no ordinary man [edit: as established above, or whatnot]. Perhaps he has super-strength? Perhaps it’s a requirement of ring distributors to lift 80 lbs. one handed while smiling?
Interpretation 3: The man is a pan-dimensional alien demi-god/prophet. With his special knowledge of the future he’s trying to tell us that the next time we play poker we should keep all hearts 10 and higher no matter the circumstance and bet as if insane(ly confident!). You are guaranteed a royal flush, and your life will cease its lonely, pedantic, ooze towards death, or whatever. Perhaps in an effort to effectively communicate with creatures trapped in the dregs of the space-time continuum, the creature utilized an idiomatic phrase that he learned in Language School for Pan-Dimensional Beings. Unfortunately, being a pan-dimensional alien demi-god/prophet with better things to do, he didn’t learn the name of the team on the field, and failed to foresee that the Cards/cards association would override our ability to interpret his extra-dimensional charity.
Assessment: Very likely. Occam’s Razor states that if you make the least number of assumptions while still assuming the presence of pan-dimensional beings, you are guaranteed absolute truth. Thus, this interpretation seems highly likely. I believe this to be an intentional, logical, rational, simple, Occam’s Razor-certified attempt by a pan dimensional alien demi-god/prophet to help us gain a poker advantage. That, good readers, is what that man’s sign means.
*Based on the 2004 Red Sox ordering 500 World Series rings, which might be on the high end.