probably just normal variance. monthly shooting percentages are really noisy.
Edit: I ran the numbers, and the difference in his shooting for january vs february comes out right at p=.05. So you can interpret that as evidence that something has changed, but there's just so many equally plausible comparisons you could make, for example february vs rest of the year (p=.08). Or you think of it as, the chance that someone on the C's would be slumping at least this badly just by random chance this month compared with last is about 50%, and even more than that for this month as compared with the rest of the year.