I took a look at the current EqA for the Cubs and compared it to the EqA that was projected for each player by PECOTA. For those who don't know about EqA - it is basically a number that takes all offensive contributions by a player into consideration, adjusts for ballparks, and normalizes across the league. A league average EqA is .260. The following chart shows the actual EqA and the PECTOA-projected EqA for each player:

Player   Actual EqA   Proj. EqA     Difference
Pierre      .214          .253           -.039
Cedeno    .246          .243          +.003
Walker     .261          .260          +.001
Ramirez   .242          .294           -.052
Barrett     .282          .262         +.020
Jones       .260          .258         +.002
Murton     .266          .260         +.006
Hairston   .229          .251          -.022
Perez      .162          .221          -.059
Blanco   -.104          .224          -.328
Bynum    .185          .241          -.056
Mabry     .176          .251          -.075

The only player that is significantly overperforming his projection is Michael Barrett. Four everyday players are performing to about where they would be expected to perform:

Cedeno, Walker, Jones, Murton

The rest of the team is significantly underperforming their projections, headed up by everyday players Juan Pierre and Aramis Ramirez. Furthermore, the entire bench is underperforming, even when considering their already low projections. And yes, Henry Blanco somehow has a negative EqA - I didn't even know that was possible.
So, I guess what I'm getting at here, is that the offense stands to improve significantly over the remainder of the season, if for no other reason than regression to the mean. I don't think anyone expects Juan Pierre and Aramis Ramirez to finish the season with their current numbers. Michael Barrett may come down to earth just a bit, but the majority of the roster has nowhere to go but up. Whether that offensive improvement translates into more victories remains to be seen.