Pirates.com:

Huntington has indicated that there are still checkpoints the organization would like Walker to meet in the Minors before earning a promotion. However, if LaRoche doesn't show improvement by Spring Training and Walker does, Walker may force management's hand to rethink its initial stance.

"Andy has already done some things at Triple-A that we are anticipating Neil will do," Huntington said. "But if it's not Andy, then certainly Neil Walker becomes a candidate."

Huntington also brought up the possibility of "creatively exploring" other options through the free-agent market or the waiver wire this offseason to bring in an external solution for third. However, with the Pirates hesitant to impair the development of both LaRoche and Walker, such a move seems unlikely.

The idea that Walker could compete for the starting third base job in Spring Training is absurd; he was so bad this year in Class AAA that there isn't much choice but to send him back there. 

What I suspect we will actually see is that the Pirates will acquire some cheap free agent, possibly on a minor league contract, to fill in for a while in case LaRoche can't put himself together. Russell Branyan would be excellent--he hits very well, is left-handed, and can also fake his way around in the outfield corners or at first. He can't field, but that's okay. At the very least, he could spell LaRoche against tough righties and let LaRoche pile up a disproportionate number of at bats against lefties. He's not really a pull hitter, but he did hit a bunch of homers to right field this year.

I still heartily endorse LaRoche as the Pirates' starting third baseman next year and wouldn't want the Bucs to sign anyone who might call that into question, but I can understand why they'd would want to hedge their bets a little, particularly if they can get a player like Branyan who'd be useful even if LaRoche hit well.