Want to know why the Birds were 15-8 in April? Just check out the chart below. Monthly leaders are Bolded. All information is from Fangraphs.
I'm not certain what the NL average wOBA is month to month. (I'm guessing between .320 & .330. If someone can be so kind to determine this for me, I'd be grateful). What the chart shows is that the Cards had great production from eight players in April, with Yadi being pretty close to average. In May we have a huge gap between the top 5 (AP, Freese, Holliday, Lopex, Luddy) and the rest (Stav .333, then Yadi at .299).
June saw the resurgence of Rasmus, Holliday, Pujols--all over .400 wOBA, and the emerging Jon Jay. That .769 is just 6 PAs but was the sign of great things to come. So the other three basically carried the team as the pitching declined and the rest of the offense tanked.
July saw Jay and Ludwick go over .400 wOBA, while Holliday, Greene (!), and AP posted better than .360. Boog disappeared (.198) and Raz went into his slump (.290). But there was enough offense for the 8-game winning streak.
It's interesting to see the wide variation in Raz's and Albert's performances month by month. Raz's poor July was offset by Jon Jay's incredible (and unsustainable?) months. Allen Craig will have to pick up his performance so that he and Jay can match the newly departed Luddy. Albert has been helped by Matt Holliday's steadily improving production.
Freese's return is a huge help, as will be Lopez's shift to 2B. It would also help to have Tyler Greene platooning there, but he is on the DL and probably other issues as well (Doghouse?).
Boog & Yadi have a LONG way to go to get being productive offensively. But they get a pass for their defense IF the rest of the guys are producing.
Miles, Stav, LaRue, Skip (sigh), and Winn really don't add anything offensively, and you can certainly make the case they have no business on the roster. Or their playing time should be limited.