I am going to chalk Locke's second half to inexperience and fatigue as much as anything. If you look at his numbers in the minors, he traditionally has had a very good WHIP and strong K numbers. His biggest concern to me has always been his K to Walk ratio, and his numbers last year did nothing to eliminate those concerns.
As for Sanchez, his biggest attribute is his ability to call a great game and his defense. With a crop of young arms coming through the ranks, even if that remains Sanchez's biggest value, he is worth picking up.