Because Robertson allows 14 baserunners a game and an ERA of over 4, and if you average 14 runners a game against a lineup such as the Cards, regardless of what kind of a rut they are in, you are begging for trouble.
Wainwright is in the same league as Carpenter and Lincecum and Halladay, and is on another planet when you match him up against a barely servicable Nate Robertson, and then when you factor in the Cards hit .333 against Nate Robertson, led by that machine that wears #5 who is 7 for 7 in plate appearences against him 4 for 4 and 3 walks well, that makes it a sound run line play.
Don't care if the number is 7.5 total, a 5-1 Card win is still a cover, so is 3-1 or 6-0
