This year's Cardinal offense is historically good. Starting in April, we knew we might be seeing something special... going by a stat called wRC+ (which is similar to OPS+ but is a more accurate and objective measure). This stat shows that the Cardinals offense knows how to get on base and execute on offense. They are very well rounded, a little more tailored to on base percentage (which has been proven to be extremely important) but still have a lot of power. In April, the Cards were 2nd in OBP and wRC+ in MLB, and 2nd in home runs in the NL.
In May, the Cardinals offense fell off in on base skills but actually put up a 121 wRC+, best in baseball, with a .191 ISO which was 2nd to the Orioles. These rates were good for 151 RBI, 42 home runs, and 157 runs (all most in the NL). Both months the team stole a fair amount of bases as well, adding a dimension of speed to the team that had not been there for a while.
Oddly enough, this amazing offense took a month off in June, and only had a 94 wRC+. The team OBP was a decent .327, but they only hit 24 home runs and the ISO took a dive (only 6 teams in MLB had worse than .129). It really seems as if the team ran out of gas in June offensively, the stolen base total even being down quite a bit.
July saw the Cardinals back to their usual NL leading ways with a 119 wRC+, bested only by the Angels. The Cardinals got on base at a .362 clip. This showed a different aspect to the offense with less power and more on base skill, due in large part to a very high walk percentage of 10.4%. Home runs were at 24 again though, which meant that May's outburst was a bit of a fluke (all other months are at 24 home runs).
In June and July combined, the Cards hit 48 home runs, which is not that much more than they hit in May. July's ISO was not that bad though, good enough for 8th in MLB. Avoiding looking at June's offensive woes makes this offense look a lot better, but it's part of the overall picture. Beyond that, it seems to be a multi-faceted offense that can walk, hit home runs, and get a lot of hits along with some speed.
That off month in June really has cost the team so far in being a historical footnote, although if the season were to end now they would still be pretty damn good. At the least they are the best Cardinals offense in a century with their current 113 wRC+. Still tied for best offense in MLB, they may not be historically amazing, but they are still a very dangerous force in today's game. Something like a top 50 offense in the past 100 years is pretty great to watch.
Matt Holliday leads this offense with his 159 wRC+, which is 9th in MLB between David Wright and Josh Willingham. David Freese has found his opposite field stroke again and is 17th in MLB in hitting: .385 OBP and 15 home runs. Giancarlo Stanton and Melky Cabrera are at this level. Freese could possibly reach around 5.5 WAR this year. And then there is Carlos Beltran and his 24 home runs leading the team (tied for 10th in MLB). Carlos is roughly a top 25 hitter in MLB, tied in wRC+ with Billy Butler and Joe Mauer.
On many teams, that triumvirate of offensive onslaught would be enough, but the 2012 Cardinals go further than that: elite defensive catcher Yadier Molina is also a leading hitter (top 30). All of these guys have at least 15 home runs so far.... an impressive feat. But wait, there's another guy with 15 home runs! Another thing that could have put this team over the top offensively is if Allen Craig was around all season, and/or if Berkman was not hurt.
Allen Craig: 149 wRC+, 15 home runs
Lance Berkman: 146 wRC+, .211 ISO
Going forward, this offense should mash the remainder of the season... and I of course would like to see them overachieve and erase that mar of June's wRC+ result... if they can do that, this offense may not only be historically good, but historically great.