Any player here would be subject to due process. Any player out of the U.S. could have their re-entry blocked because of allegations. Entry to the U.S. by non-citizens is a privilege granted at the pleasure of the U.S., not a right.
Having said that, I suspect that the chances of Tejada being barred from returning this year are pretty much zero. If this thing snowballs, however, and he's formally busted, then he's got a big problem.
What are the US laws for people (like ballplayers) who come in on work Visas and return back to their home country? Specifically say in the area of steroids. They are illegal to purchase and use here without a prescription, but if you buy and use them outside of the country, that shouldn't matter to the government, right?
It is not like their use outside of the US is a threat to the US when they come into the US, right? So while they can deny access to anyone they want, would this reasoning fly? "We denied his work Visa because we discovered he did something in his country that they don't consider illegal, but we do."
I am not talking something like murder or anything like that, but more along the Steroid use level.
I know it is outside of the scope, because supposedly Tejada bought and used them while in the US. Just wondering.