Take it however you like, but Neal Huntington says that the Super Two issue is "not a defining factor" in the timing of Gregory Polanco's promotion:
"He’s continuing to refine some of the intricacies of his game," Huntington said. "Somebody asked the other day for a detailed list of what he’s working on. When Andrew [McCutchen] was coming up, I gave a detailed list as to what he was working on, then watched major league teams attack those weaknesses I’d identified in spring training. So, I’m not going to give you a detailed script that opposing teams can attack when Gregory gets here."
There's surely no doubt that the Pirates are trying to help Polanco continue to improve, but the Super Two issue remains the best reason not to promote him, whether or not Huntington admits it (and he shouldn't). If Polanco is going to be a star, then promoting him now as opposed to the second week of June might mean paying $10 million or more in the long run for 35 games or so in 2014.
Tim Lincecum was a Super Two player, and his case provides an extreme example of how much Super Two eligibility can cost. Lincecum became arbitration-eligible right after winning a Cy Young award and made $9 million in his fourth season in the league, then $14 million, $18 million and $22 million in his next three seasons. Clayton Kershaw, who was not a Super Two player, made $500,000 in his fourth season in the league, won a Cy Young in that season, and then made $7.5 million and $11 million in his first two years of arbitration eligibility before agreeing to a long-term deal. It's hard to find exact comparables when you're dealing with players at the extremes like this, but you can see how much money the Dodgers saved, in part because Kershaw did not have Super Two eligibility.
Bringing Polanco up now certainly could cost the Pirates less than $10 million or so. But if Polanco isn't going to be a star, the sort of player who could make a big impact in six weeks (and, therefore, the sort of player likely to get huge arbitration payouts later), then calling him up now wouldn't make much of a difference anyway.
These are the only contexts in which promoting Polanco now would make sense:
1) Polanco projects to be a great player this year, but not in two years, when he would be heading into arbitration for the first time.