Brian McCann of the Atlanta Braves came back from an injury on August 14th, and but his offense has not recovered. His .174/.296/.347 slash line stands as one of the reasons the Braves have slid to a one-game lead over the Cardinals in the NL Wild Card race. McCann injured his left oblique muscle, and it appears the injury hurt his swing.
McCann is swinging about the same amount, but missing much more. That's puts him a hole more often, which makes Brian even more vulnerable. The numbers say to me that his bat speed hasn't returned. He's timing pitches like he was healthy, but he just can get to them as quickly as he did before.
You can see this graphically in his contact rate:
McCann covered the plate well before the injury.
McCann can't handle high pitches, where a hitters bat needs to be quicker, and he also has problems with the outside half of the strike zone. He may not get his timing back until he has time to heal fully this off-season.