behalf, but the player still has to pay US taxes to the IRS. I believe the player pays what is called a "hypothetical" tax to his employer, which is the amount of tax he would have paid had he stayed in his home country, and the employer pays the difference. This is a standard expatriate benefit that most employers provide when they send people overseas -- I've done several overseas assignments, and this is the way it worked for me and the vast majority of expats I knew. So it isn't really tax-free, it just protects you from paying incremental taxes in the "host" country, above and beyond what you would have paid in your home country.

I don't know for sure that this is the way Mika's employer does it, but I believe this is the standard practice for US athletes overseas, based on what I was told by several pro athlete friends who lived in the cities I lived in overseas. Their tax benefits were essentially identical to mine, which were what I described above.