This malaphor headline comes to us from the Olean Times Herald: http://www.oleantimesherald.com/sports/pollock-bills-mcdermott-starting-to-look-over-his-head/article_5bf52096-cfe4-11e7-9e3a-1b4137e0f0fe.html
If you clicked on the link, you will see that the author of the article inadvertently mentions the two sources: “in over your head” (too deeply involved in a difficult situation) and “looking over your shoulder” (insecure or anxious about a potential change). This is another classic “head/shoulders” mash up. I have posted numerous others. A shout out to John Costello for spotting this one.