Some MLB teams plan to ask umpires to check pitchers for foreign substances, sources say

Baseball's rule against the use of foreign substances has been buried for decades underneath a gentlemen's agreement that held among managers, who almost uniformly refused to ask umpires to check opposing pitchers because they knew that their own pitchers would not be checked.

But with Major League Baseball set to order umpires to enforce the foreign substance rules starting Monday, at least three teams intend to set aside that old gentlemen's agreement, according to sources. If the managers of those teams receive information that seems suspicious -- video of an opposing pitcher perhaps capturing the use of foreign substances, or data about an unusual spike in spin rate -- they will ask…