Here is Diamondbacks' most difficult decision they will face this winter

The Arizona Diamondbacks have been one of the top teams in the National League this year. They are red hot and currently ahead of the rest of the pack in the Wild Card race.

However, they may face some uncertainty this offseason with a key slugger, Christian Walker set to enter free agency.

Joel Reuter of Bleacher Report listed Walker's free agency as the toughest decision Arizona will face this coming winter.

"A late bloomer who didn't become an everyday player until his age-28 season, Walker will turn 34 just before Opening Day next year," Reuter wrote. "That might work in Arizona's favor, as it will limit the number of years he can realistically expect to receive on his next deal."

This will be a tough decision for Arizona because there are going to be several key first basemen on the free agent market this offseason. They could choose to keep Walker or go in a different direction.

Pete Alonso will be the most coveted first baseman on the market, so Arizona could take a look at the New York Mets slugger. They could also reunite with Paul Goldschmidt, who is unlikely to stay with the St. Louis Cardinals this offseason.

But Arizona will have to decide which direction they want to go in free agency. They might be best served keeping Walker around, but he isn't their only option. His age will likely make him very affordable for the Diamondbacks, who are trying to build a sustained winner.

We'll see if they ultimately keep him or choose to look elsewhere.

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