UPDATE: Are the Red Sox out of it? And will the Padres get multiple deals done?

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UPDATE: It's being discussed...

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The Chicago Cubs and San Diego Padres have been involved in trade discussions for a decent while, as previous rumors have linked the Cubs to Padres' starters Tyson Ross and Andrew Cashner. Now the Boston Red Sox have hopped into the picture.

Here's the latest from ESPN Insider Buster Olney:

Boston's involvement in such trade discussions broke this morning when ESPN's Jerry Crasnick said the Red Sox are "in the market for controllable starting pitching" and "like Tyson Ross a lot." FOX Sports' Ken Rosenthal also mentioned Boston could be looking at Padres' closer Craig Kimbrel. However, the Yankees are interested in Kimbrel and have been talking with San Diego since last night and the Astros like him as well.

What we do know is the Padres want a young shortstop, having previously expressed interest in Cubs' prospect Javier Baez and Yankees' prospect Jorge Mateo. The Cubs have Baez and Starlin Castro to offer while the Red Sox have Xander Bogaerts (who they probably won't be willing to move) and Javier Guerra (their No. 7 overall prospect). San Diego is also hoping to get rid of some big name players, impending free agents and costly contracts, which means Kimbrel, Justin Upton, James Shields, Ian Kennedy and others could be gone before today at 4 p.m.

It's been said the Cubs are not interested in Shields, but perhaps the Red Sox are if they really want some stability atop their rotation for the foreseeable future. Kimbrel, Upton and Kennedy have all been linked to Chicago in some capacity as the Cubs are in need of an established closer, a left fielder and starting rotation depth. Both the Cubs and Red Sox have also talked to the Cleveland Indians about starter Carlos Carrasco, so maybe one of the clubs is progressing toward a deal for him while the other is keen on getting Ross.

"Ross is the most attractive of that group [of Padres' starters], and the Cubs are the hottest on him, according to one source," Rosenthal added in his column this morning. "[Will ]Venable and other Padres players also appeal to the Cubs, raising the possibility of a blockbuster; the Pads have been chasing a shortstop for a month, and the Cubs could send them Javier Baez, Starlin Castro or even both."

The Red Sox have been getting calls on relievers Koji Uehara and Junichi Tazawa, which could indicate their eventual departures followed by the acquisition of Kimbrel.

Both Boston have deep farm systems and the Padres desperately need to replenish theirs after making countless trades in the offseason that involved their top prospects.

Here are some top prospects the Padres could be taking a look at from both of these clubs:

Red Sox: Henry Owens, Brian Johnson, Manuel Margot, Deven Marrero, Rafael Devers, Javier Guerra, Garin Cecchini

Cubs: Javier Baez, C.J. Edwards, Billy McKinney, Albert Almore, Arismendy Alcantara, Gleyber Torres, Duane Underwood

Obviously everything is speculation, but a lot of things match up here and it'd be good to keep an eye on what develops between these three clubs as the deadline approaches in less than four hours.