I have lately noticed a tendency, at least in the US, for sports commentators to change nouns into verbs. For example many American football broadcasters will now say a player "lost contain" of another player instead of "he lost containment." This seems to be improper usage. Is this an example of our language evolving to simpler terms, or is it limited to sports?
Yes, this is a trend that is becoming more and more common, but it's not a new thing. There are lots of examples of nouns becoming verbs, e.g. you can 'gift' a present to someone. And you come back from a presentation with 'learnings' (the things you learned). Both of those are way older than you'd expect.
But verbing nouns and nouning verbs is pretty productive in English and has been for a while. This is usually ascribed to English lacking a lot of inflections that would normally differentiate a verb from a noun, so the same form works for both. But frankly even in a highly inflected language, like Latin, there's always a way to have inflections change to give the root in a new part of speech (e.g. amare - to love amor (love itself) ).
Some word-smithing professions have a culture of invention and sportscasters are one of them. So you're likely to hear all sorts of innovative things from them.
Have you ever noticed that some words are both nouns and verbs? I'm sure you can probably think of many such words (here's a list although it's by no means comprehensive). Usually this happens because the verb was formed from the existing noun, or the noun from the verb (and sometimes it's another part of speech that's the origin of both the noun and verb forms). This process has always happened in English.
The process is called "conversion" or (if the word becomes a verb) "verbing":
Technically, this very common process in English is known as conversion: it converts a word into a different part of speech.
One particularly common form of conversion is using nouns as verbs. This specific process is called verbing.
Oxford Dictionaries: Verbs from nouns
According to this source, conversion is so popular in English because English has so few inflections.
For example, the OED says that "window" (verb) comes from "window" (noun). The earliest attestation the OED has for "window" as a verb is Shakespeare's Antony & Cleopatra.
Another example is "pepper", which was formed from the noun at some point in Old English according to the OED.
However, the example in your question doesn't sound right to me for one reason: blocking. Because there is already a noun (containment), we don't need another noun.
I personally don't care that this isn't a discussion form, there isn't enough traffic on this site for it to matter to me.
With that said I would say it is an evolution of language, but I would argue it is not necessarily a simplification. I imagine if this continues both words will fit into a preferred context, rather than one replacing the other.
This is all opinion and I have no credentials.