Look at the last 889 MLB PA that Brian McCann had prior to this season.
Over that period, he hit .242 – including the second half of 2013, where his BA/OBP/SLG line was .220/.296/.384 (in 196 PA).
Next, look at his Spring Training BA/OBP/SLG line this season: .200/.265/.333 in 49 PA.
Lastly, note that his BA/OBP/SLG line to start this year is .152/.176/.152 in 34 PA.
At what point does this become worrisome?