Let’s see who is the first result on Google search “Michael Jordan”, “Kobe Bryant” and “Lebron James”

Kobe with Jordan are the first results on Google for their names while Lebron is third. So if the amount of people clicking first search result is approximately the same, then more popular player would be the one who has the most page views per day.

Luckily, there is a service that can show you how many times a particular Wikipedia page was opened on every day. I ran 3 searches and now see that Michael Jordan is more popular than Kobe Bryant and Lebron James because on average Michael Jordan wikipedia page is seen by more than 10 thousand people while Kobe and Lebron is in the range of 6-8 thousand page views.

Michael Jordan on Wikipedia

Kobe Bryant on Wikipedia

Lebron James on Wiipedia

p.s. strange that on September 23 there were 0 page views for Lebron James according to this graph.