[Cloud]

no, I think "sports teams" is either a compond noun or a noun phrase. The proper possessive would be sports teams' something. My Chicago Manual of style says this:

"in compound nouns and noun phrases the final element usually takes the possessive form. [such as:]

student assistants' time cards." Except there's no possessive here, right?

for an opposite reaction (thereby making me wrong) it says:
"the line between a possessive or genitive form and a noun used attributively--as an adjective--is sometimes fuzzy, especially in the plural. . . . Chicago dispenses with the apostrophe only in proper nounts or where there is clearly no possesive meaning:

the women's team (clearly possessive)
a consumer's group

It's a pretty hard grammatical problem, but I really don't think there's any possessive there, so I still think no apostrophe