It's a method of drawing attention to important text; URL bars in Chrome, Firefox and IE do it now to draw focus on the top level domain, arguably the most important part of the URL,especially when trust and security are issues.
However ESPN's method seems to be a case of extreme over application. Rather than optimizing the content for scanning they have harmed it, as only one paragraph out of ~10 (in that article) is highlighted, and the rest is grayed out. This has multiple negative effects in this context.
Contrast is reduced for the majority of the content: This is okay in a URL bar as (presumably) the user cares less about the non-highlighted text, and more importantly there's not much of it. You don't sit down and read a single URL for 5 minutes. When you reduce the contrast of a whole news post you're just hurting my eyes (and OCD! Come on!)
Context is eliminated: My eyes are drawn right from the headline "Cowboys' Tony Romo does not practice" to the sentence "The puncture has been described as "small". That doesn't make any sense. I assume that this puncture happened to Tony Romo, maybe even with some extra thinking I can assume it's related to his lack of practice, but I have no idea what this puncture is. Focus should be drawn to the major points in context. Out of context, the fact that "the puncture" was "small" is meaningless.
Regarding whether it was deliberately I'm not entirely sure, but I don't believe it was done competently. Looking in the CSS that paragraph is simply missing the
<p> tag. The fact that it is must be deliberate to a degree, but I can't imagine why they would be doing so, since they're trying to apply style to the whole article.