The Yankees expect to have A-Rod on Monday against the White Sox because they believe he will be suspended under the Joint Drug Agreement and not under the CBA, as MLB had previously threatened (Update: Joel Sherman is now reporting that the Yankees have been informed he will be suspended tomorrow and Selig will not use the CBA. A-Rod will play tomorrow if he appeals). Joe Girardi was able to tell reporters he has Alex penciled in for tomorrow because a player suspended under the JDA is entitled to an appeal and an automatic stay of the suspension whereas the stay does not exist under the CBA.
What's curious is the duration of the suspension. The JDA contemplates specific lengths for specific offenses: the first is 50, second 100 and a third is a lifetime ban. Alex Rodriguez has never failed a drug test under the Joint Drug Agreement. We don't know the details of MLB's evidence—only that there are "volumes" of it—but if MLB suspends A-Rod for 100+ games under the JDA, the numbers will have been fudged.