The San Diego Padres and Chicago Cubs have what the other needs, and a deal might be in the making.

Sources tell FOX Sports' Jon Morosi and Ken Rosenthal that the Cubs and Padres have discussed a deal that would send shortstop Starlin Castro to San Diego, potentially in exchange for one of the Padres' starting pitchers.

If a deal comes to fruition, the Padres would fill their need for a mainstay shortstop, and the Cubs would add a talented starter to their rotation as they make a push for the postseason.

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Morosi speculates that a deal for righty James Shields in exchange for Castro would make the most sense for both teams.