I've wondered about Jordan, because a) he competed at a high level at an older age, b) towards the tail end of his career he got a lot bulkier, and c) the back-9 of his career coincided with an explosion of steroid use in baseball. But we'll likely never know. If Jordan used, he likely wasn't the only one from that era. Have you ever seen a picture of Corey Maggette? Karl Malone? Ben Wallace?
I'm more concerned about who's using it in basketball right now rather than in the past. Think of the astounding things happening all at the same time. Lebron is the easy target -- huge muscles, faster and stronger than anyone else on the court, playing with boundless energy in the playoffs after leading the league in minutes/game at age 32. But Russell Westbrook also just averaged a triple double for the first time in 45 years, playing in 81 games this year. There are other examples, but let's just say the past couple of seasons -- and especially this season -- of NBA basketball feels weird.
I actually wanted to start a running thread on PED use in basketball and sports. I realize some people don't care, but I do.
You can come up with other explanations for the explosion -- offenses have just evolved, we're seeing a unique era in terms of top-tier players, etc. -- but keep in mind that baseball had similar explanations before everyone looked back to the 90s as an era where players were obviously juicing.