The Cubs have just played 15 games straight and a bunch of regular hitters have either gotten no time off or are still coming back from injuries. It's an early game after a late one against a team that really isn't all that "important" in the grand scheme of things being fronted by apitcher that has a really good chance of shutting down the Cubs even if all the best bats are there and at full strength. It's kind of a perfect storm in terms of getting guys a break.