By definition, inflection is: " change in the form of a word (typically the ending) to express a grammatical function or attribute such as tense, mood, person, number, case, and gender."
In this case, the original form of the verb is To Play.
The verb's inflection, "-s", indicates a tense. Plays is in the present tense. But the conjugation is used for the third person (singular), such as he, she, or it.