The postseason numbers are only through 4 or 5 games, so it is difficult to make too much out of them. They can easily turn around once a team moves onto the next round and faces new pitchers, but they should be a cause for concern for several teams.
The ability to hit with runners in scoring position was a huge advantage for the Cardinals all year. They had a batting average of .330 with RISP, an unbelievable 48 points ahead of the next closest team (Tigers, .282). Oddly, they were 2nd worst when there was no one on base (.236), making it a very important part of their offense (especially since they were 27th in hitting home runs with only 125). This would be a real problem if they have to play the Dodgers, another team with excellent pitching (ranked 2nd in team ERA with 3.25).
The same goes for the A's. The A's can compensate by hitting home runs, but they would need to drastically improve their .395 OPS with RISP against Boston.
The Red Sox have been very consistent between the regular season and the postseason, and that would likely continue into the ALCS.
It probably comes as a shock to people that follow the Tigers that they hit so well with RISP in this series since their offense had been silent until the last few innings of Game 4. They would need to keep that up to have a shot against the Red Sox with Miguel Cabrera injured and struggling.
The Pirates also need to keep this up because their pitching might not be able to completely keep the Dodgers down if they make it to the NLCS and don't have a lineup that easily generates runs.
This is one of the key stats to watch as we move in the next round. If they Cardinals don't start hitting in the clutch again, they are probably going to have trouble making it past the Dodgers if they win in Game 5. Most of the remaining teams in the playoffs hit well with RISP this season, but they could be heading home if they don't start doing it in the postseason.