I am very sorry that the post you wanted to link to, Gustavo, is imprisoned inside the Moderation Queue and hope soon to be able to rescue it, along with the many thousands of other posts in the same boat. As you know, I am waiting for a guarantee from Tech Support that content that has been "approved" (i.e., released) from the Moderation Queue will in fact manifest in the actual threads. Once I have that, I will release all of those posts ASAP.
- Lionel Messi is the greatest player of/in the Argentina football team.
In American English, the best preposition to use in that example is "on." In Rachel's answer, a quote from Swan is given in which he uses "in" in a similar example, indicating that British speakers find it OK to say "the best player in the team." I believe they use "in the team" in other cases, too, like "he got in the team." In American English, it's "got on the team." On COCA, there are 16 results for "the best player on the team" and none for "the best player in the team."