Over the weekend it was noted the Chicago Cubs are searching for a starting pitcher as well as a left-handed outfield bat. But is it too soon to think about their middle infield situation as it's expected Addison Russell will be shifted over to shortstop perhaps before the trade deadline?

Trade rumors have engulfed Starlin Castro for a while now because it's been said Russell is the shortstop of the future. Castro is one of the league's better shortstops and is under a team-friendly contract through 2019, but his current .254/.290/.329 stat line is not helping his trade value.

"The Cubs would be a better all-around team if they traded Starlin Castro and added a veteran shortstop or second baseman to pair with rookie infielder Addison Russell. The issue is whether any team is interested in Castro - at least, for the full amount left on his contract (four years and more than $40 million after this year)," writes FOX Sports' Jon Morosi.

Nonetheless, there's still a strong possibility teams express interest in Castro before the deadline. The Cubs may not get exactly what they want in return, but it's perhaps more important to put a lock-down defender at the shortstop position.

"True, the Cubs' infield is stacked. But the team could trade Starlin Castro to make room for Addison Russell at shortstop," FOX Sports' Ken Rosenthal added. "Javier Baez could play third if Kris Bryant moved to left, or fill a super-utility role."

Rosenthal also noted the Cubs "are expected to consider" second baseman Howie Kendrick in the offseason and acknowledged Ben Zobrist and Daniel Murphy will be free agents after 2015. Chicago has been linked to Zobrist in various trade rumors so it's possible they look to make such a move as early as this month, but they may not want to give up prospects for a rental considering they might do that to acquire a starting pitcher.

The Los Angeles Dodgers are unlikely to move Kendrick since they'll be contending for an NL West title (and may have interest in re-signing him) and the New York Mets have had enough issues with their offense that it would hurt them to part ways with Murphy before the deadline. Zobrist is the only one who will likely be traded and there will be plenty of suitors for the versatile veteran among top contenders, which will likely hike up his price in a deal.

All three will be free agents in the offseason and that's probably when Theo Epstein and Jed Hoyer will strike. But that may not change their trade plans with Castro before the deadline because Javier Baez is expected to return from his broken finger soon and he can take over at second after Russell shifts over to short in the event Castro is dealt.

The rumors surrounding Castro have been relatively quiet as of late, so it's largely unknown if the Cubs will look to trade him before the deadline, during the offseason, or at all.

The one thing to take from all this is that Chicago is likely looking to upgrade their defense up the middle and that makes Castro the top casualty at some point - it's just unknown when. Otherwise, look for the Cubs to acquire a starting pitcher, closer and outfielder at the deadline because all of those areas of need are much more immediate.

Just remember Zobrist, Kendrick and Murphy will be among those considered during free agency.