Unfortunately for fantasy baseball players, I'm relatively certain that the St. Louis Cardinals will not play Albert Pujols at third base enough for him to earn eligibility there. It's not a matter of his lack of ability there so much as his almost-constant gimpiness and the nervous standing of his elbow ligaments. (Pujols was moved to first base originally because his elbow was a ticking time-bomb in left field. [Also because he wasn't a great left fielder].)
But when he came up in 2001 he was actually a perfectly solid third baseman—no immobile Miguel Cabrera, for instance. You can see this when Pujols plays first—he's got a kind of live-wire energy on defense, and incredible reflexes, which made up for his average arm at the position. In his two years at the position—about 90 starts in 2001 and 2002—he was worth one run above average at the position, according to Baseball-Reference and Total Zone.
But the Cardinals were never especially confident about young Albert Pujols's defense, and the acquisition of Scott Rolen moved him off the position for good. Tino Martinez kept him in the outfield for a few more years before he was finally able to move to the position that seemed made for him all along.
Until the Cardinals ran out of infielders Sunday afternoon.