If you strongly favor statistical analysis, then your stance on RISP numbers is that it is not a predictive value. So while the St. Louis Cardinals have an amazing .330 average with runners in scoring position, going forward they should be expected to be closer to their .269 average overall.
It's not a surprise that previews from people who think this way are picking the Pirates over the Cardinals in the NLDS.
Rany Jazayerli has a great preview on Grantland, and predicts that the Pirates will win in four games. Jazayerli sums up the impact of the RISP numbers, and the Pirates defensive shifts, here:
The Cardinals' offense is also highly dependent on balls in play to succeed. The Cardinals were second in the NL in singles and first in doubles, but were just 13th in home runs. The Pirates, who have a sensational defense (third in the major leagues in Defensive Runs Saved) and who aggressively use defensive shifts to gain an edge, are a poor matchup for them.
Tim is the owner and editor in chief of Pirates Prospects. He started the site in January 2009, and turned it into his full time job during the 2011 season. Prior to starting Pirates Prospects, Tim worked with AccuScore.com, providing MLB, NHL, and NFL coverage to various national media outlets, including ESPN Insider, USA Today, Yahoo Sports, and the Wall Street Journal. He also writes the annual Prospect Guide, which is sold through the site. Tim lives in Bradenton, where he provides live coverage all year of Spring Training, mini camp, instructs, the Bradenton Marauders, and the GCL Pirates.