The Chicago Cubs are subjected to a lot of speculation, beginning with who they'll acquire via free agency. But let's not forget a number of teams around the MLB are interested in their young shortstop Starlin Castro, who could provide a nice return in a trade.

Castro is turning 25 next season and has been one of the league's better shortstops throughout his five-year career. He's slashing .284/.325/.410 with 51 home runs and 294 RBIs over that span and his rebound season in 2014 perhaps suggests his trade value is at its peak. Chicago acquired 20-year-old shortstop prospect Addison Russell from the Oakland Athletics in July, so is it possible Castro could be on the way out?

Russell was invited to the Arizona Fall League, but was shut down in late October because the team wanted to give him a rest before his offseason conditioning program began. The youngster had a poor 11 games, slashing .196/.260/.348 with two home runs and nine RBIs, but added seven stolen bases. However, he had a solid 50 games at Double-A Tennessee with Chicago, batting .294/.332/.536 with 12 home runs and 36 RBIs. According to MLB.com's Prospect Watch, Russell is expected to make his debut at some point in 2015. Castro may help the Cubs fill another roster need if they trade him, especially if they strike out in free agency.

The New York Mets have been vocal about their pursuit of a shortstop this offseason and they seem to be an appropriate trade partner for Chicago. ESPN's Buster Olney recently mentioned the Cubs could seek pitchers such as NL Rookie of the Year Jacob deGrom or Zack Wheeler, who had good 2014 campaigns in the Mets' starting rotation. New York also has Noah Syndergaard in Triple-A, who they reportedly offered to the Colorado Rockies in a package for shortstop Troy Tulowitzki before this year's trade deadline. Whether or not the Cubs manage to land a top-tier free-agent pitcher, exploring this trade option would help them bolster their starting rotation, which is what they need.

A number of other teams are in need of a shortstop, including the New York Yankees, Los Angeles Dodgers, Philadelphia Phillies, Cincinnati Reds, Seattle Mariners and others. Aside from the Mets, only the Reds look like they'd be most likely to explore a trade for Castro. The Yankees don't have much to offer because their farm system is depleted; the Dodgers have Corey Seager in the minors and would probably prefer a shorter-term solution at the position; the Phillies are stuck with Jimmy Rollins for 2015 and he wants to stay in Philly; and the Mariners' pitchers are either too good or not good enough to execute a trade for Castro.

What could be interesting is the Reds' potential willingness to trade starter Johnny Cueto. The right-hander was fourth in the MLB in ERA (2.25) this past season, third in WHIP (0.96) and second in wins (20). The Reds picked up his $10 million option for 2015, but their significant decline in 2014 suggests they may have more problems than many believe. ESPN Insider Mike Petriello writes:

"This team, as constructed, doesn't look like a playoff contender. There are plenty of holes in the lineup and limited dollars to fix that. Once again, the most appealing Cincinnati trade chip is a top pitcher entering the final year of his contract. This time, the Reds can't make the same mistake [they did with Homer Bailey] and stand pat. It's time to trade Johnny Cueto."

Obviously, if this became a reality, Chicago would likely work to obtain a 72-hour window to sign him to an extension, because they wouldn't trade Castro for a one-year rental on Cueto.

Whatever the case, it's hard to believe Castro will be around much longer if Addison Russell continues to develop at a quick rate.