The rumored deal has at last come true, as Jon Heyman tweets:
hank blalock agrees to minor-league deal with #rays for $925,000 plus $350,000 in extras.
In other words, Blalock will make between $0.925m - $1.275m in 2010 should he break camp with the Rays. In the event that he doesn't, there is probably language in his contract stating that he can become a free agent again.
DRaysBay has more on the signing.