Last night it was reported prized prospect Addison Russell would be joining the Chicago Cubs for Tuesday night's game against the Pittsburgh Pirates. Although he's expected to start at second base, could he still be Starlin Castro's successor at shortstop following earlier trade rumors?

FOX Sports' Ken Rosenthal noted Russell will indeed play second base to start his career with Chicago, but the team still views shortstop as the 21-year-old's best position. Castro currently occupies that post and is batting .327/.353/.408 with four runs scored, one home run and six RBIs in 12 games this season and hopes to continue to be a better shortstop for the Cubs.

"I have good talent to be a good shortstop," Castro told reporters after last night's game against the Pittsburgh Pirates, via Patrick Mooney of CSN Chicago. "I don't want to be no joke anymore.

"Sometimes, the errors that I've made (in the past have come) because I don't have the confidence and stay back with the ball. Now, I'll be aggressive and challenge the ball."

Castro wanting to improve his defense by being more aggressive is something uncharacteristic of the 25-year-old, considering he's been regarded as lackadaisical and irresponsible in the field since debuting in 2010. Castro's DRS (Total Defensive Runs Saved) since 2010 is -25.

"No one is quite sure why Castro has raised his game on defense this season -- perhaps he is being pushed by prospect Addison Russell, whom the Cubs are calling up to play second base," writes Jesse Rogers of ESPNChicago.com.

Castro's name has been floated around in trade rumors, especially with the San Diego Padres. General manager A.J. Preller has been looking to upgrade the shortstop position on the Padres' roster and Castro has been rumored to potentially be an option once Russell was called up.

However, Russell's promotion was perhaps for different reasons. The Cubs have had a lot of issues at the second base position, with Javier Baez starting the season in the minors after an awful offseason and spring training, Arismendy Alcantara batting .077 thus far into the year and Tommy La Stella hitting the disabled list with a sore right side.

Rosenthal also noted Russell could be demoted at some point, but the team is hopeful he will "take off." If that's the case, and Alcantara or Baez get back into a rhythm and put their contact struggles behind them, then a trade involving Castro would make more sense. However, right now, it's unlikely Epstein and Co. look to make a move because they don't have a capable second baseman.

"Whether or not Castro stays at shortstop and Russell transitions to second base, there are ways for the Cubs to make those pieces fit together," writes Mooney.

This appears to be the case for the team in the near future, but things could be different come July.