Rob Biertempfel writes that the Pirates' Pedro Alvarez will make the team coming out of Spring Training, as long as he's healthy. Biertempfel also writes that the Pirates will "pick spots" for Alvarez against left-handed pitching, but that he will not be in a strict platoon.
This means, essentially, that if Alvarez is healthy (he's out with a knee injury right now, although that's not supposed to be particularly serious), he's the Pirates' starting third baseman, despite a miserable 2011 season and a spring in which he has struck out 13 times in 30 at-bats.
From the outside, this looks strange, but it's hard to critique the Pirates too much -- Alvarez still has upside, and the Bucs have a clearer view than we do of how best to develop him. Alvarez has an option, so the Pirates are free to send him down to Class AAA throughout the year if they choose to.
Bucs Dugout's recent podcast covers the topic of Alvarez's Spring Training performance.