One of the biggest reasons the Diamondbacks struggled so mightily this season was due to the revolving door at both third base and shortstop. Seven different players played at the hot corner for Arizona in 2012, none of which had a great impact on the position. Their collective batting average was a measly .239, which was good for among the lowest at the position in the major leagues.
After the team traded Ryan Roberts to the Rays, they acquired Chris Johnson and also played rookie Ryan Wheeler at third. Johnson started off hot for Arizona, hitting a grand slam in his D-Backs debut, but he struggled down the stretch. Because of that, manager Kirk Gibson put him in a platoon with Wheeler and journeyman Cody Ransom as the year went on. Even John McDonald got some time at third.
For 2013, this is an area the team desperately needs to improve upon. They have Matt Davidson in the minors and Ryan Wheeler could come around and improve, but someone they can rely upon day in and day out would be best. Johnson seems the most likely candidate to start at third base come opening day, but it would behoove the D-Backs and GM Kevin Towers to look for deals around the league. Even if they have to trade a young piece of their pitching core to get a corner infielder, it might be worth it.
While they are looking for a third baseman, they may also want to inquire about a shortstop. Willie Bloomquist, John McDonald and current Oakland Athletics infielder Stephen Drew managed the position this season. After Drew was shipped off to the A's, Bloomquist started having back issues and was shelved for almost the entirety of the latter half of the season. Jake Elmore was called up to get some experience at the position, but he never looked like a solid fixture. That left McDonald and Ransom as the only two capable shortstops, with Elmore filling in from time to time.
To me, this position needs to be addressed more than third base. The team has no middle infielders ready to be called up. They need a guy, much like Drew was a couple of years ago, that can play 140-plus games a season and can bat a respectable average. Bloomquist and McDonald just aren't young enough to do that anymore. Can Elmore step up? Who knows. The team could explore the idea of trading pieces to land someone like Elvis Andrus, but he may not even be available.
The left side of the infield needs some work and Kevin Towers has promised to add talent to both positions. We will have to wait and see what moves he makes, but even if he jeopardizes shaking up the future pitching rotation to land a solid infielder, I would say it would be well worth it.