Yep. Here's a numbers way to look at it. Halladay will likely miss 11 starts over eight weeks. Since he's been with the Phillies, they have won approximately 70-75% of the games he started, so we might assume that in those games with a healthy Halladay the Phillies could expect an 8-3 record.

With the replacement pitcher (Kyle Kendrick), assuming the return of Worley to the rotation, the Phillies win approximately half the starts. So if they win 5 of the 11 Halladayless games, the net result is 3 games, which is actually significant.