I think there are two lenses to look at it through..

In a vacuum when not considering the quality of their DL, or the Jagusah injury, or the youth of the LG and LT. The right side of OL was probably a solid B, the Center was a C and the left side of OL was a D-.

However, when considering the mentioned context...right side was probably B+, Center was a C+, and left side of OL would be a C+.