Sources: MLB finalizing memo on rule against use of foreign substances by pitchers

Major League Baseball is putting the final touches on a memo that will detail the sport's rule against foreign substances, with the expectation among some sources that the document will be forwarded to teams sometime in the next few days and presented to coaching staffs and players, sources said.

The actual order to umpires to enforce the rule might occur a week later, in the range of June 21, according to sources. But the elongated rollout and source-driven discussion of the foreign substance crackdown has been by design, to some degree. MLB's hope is that pitchers who use foreign substances like Spider Tack and homemade super glues will be scared straight by the public conversation and…