There are two ways of making it to the NBA: a) Being drafted b) as a free agent)
Many players don’t realize how difficult it is to make the NBA as a free agent.
If a player wasn’t drafted out of college, there is a reason for that. The NBA scouts evaluate every player in college, and there are no secrets or hidden talents there. If a college senior doesn’t get drafted, it is often because he lacks the size, the strength, or the athleticism for the NBA. Those things are not likely to change.
If a college senior is not drafted, it is highly unlikely that an NBA team will sing him as a free agent a couple of months later and then come to a conclusion: “Hey, we made a mistake. This player is an NBA player. We should have drafted him”. That will simply not happen because too many people could then lose their jobs.
Keep in mind that 90-95 % of all the players in the NBA were drafted, and most of them even in the first round. Less than a handful of undrafted players make the NBA each year. Imagine that 1.000 college seniors graduate each year and only 4 of them make it to the NBA as undrafted free agent rookies. That is a chance of 0,4 %. Think about that.
Undrafted college seniors often get only ONE shot at the NBA, so the timing of their attempt is crucial. The rule of thumb is that when the player is fresh out of college, his chances to make the NBA as an undrafted free agent are the worst. As stated before, the NBA teams have scouted all the college players, and there is a reason why they did NOT draft a particular player. The NBA opinion about him has been formed over the years by the entire scouting staff and will not simply change overnight.
If a player goes overseas to play professional basketball, he has a better shot at the NBA than when comes straight out of college. Players mature as persons, get more experienced, get physically stronger (some even grow a little) and improve their skills. One year overseas will not make much of a difference, nor will two years, but three or four will make NBA teams curious.
But the chance of getting a serious look from NBA teams depends highly on the level the player plays at overseas. If he plays on the highest level (Euroleague), then most games he plays will be scouted by NBA personnel. If he is one of the most dominant players on that level, then the odds are in his favor.
However, a player who plays in a lower level league overseas will not be taken seriously by any NBA teams and will not get a chance. Many players who have had one good season in a lower league become impatient and want to take their one and only shot at the NBA immediately. The chance that they get invited by an NBA is almost zero, but the chances of them making the team are guaranteed zero!
A non-drafted player who goes overseas and wants to work his way back to the NBA must work his way up. Once he is dominating the top international level, he will be ready to take a shot at the NBA, and then he will have a (good) chance.
If these odds seem bleak at 0,4 % to make the NBA as an undrafted college senior, then the harsh reality in regards to the expenses is even worse.
NBA players, usually get their salaries when the NBA season starts. How will an undrafted college senior survive until then? How is he going to support himself and at the same time pay for all the extra expenses that are related to professional basketball? We are only talking about real costs here. Not loss of potential earnings from turning down offers from overseas.
If an undrafted college senior is cut in NBA training camp, then he has a serious problem. He is probably stuck with debt and most likely missed out on lucrative deals from overseas while he was dreaming about the NBA. There is even a chance that he may have to sit out an entire season unless he gets a replacement job for another player who was cut or got injured.
Imagine that an investor walks up to you and asks you to invest $ 50.000 and the chance of ever getting that money back would only be 0,4 % ?!!? The chance of losing it all would be 99,6 %. Imagine that he would also ask you to walk away from a six-figure job while you are waiting to see if you will ever get your investment back. Just think about that. Nobody in the world would invest that amount against those odds, but when it comes to the NBA, then it seems like people can not think rationally anymore.
It is a returning story every year. Every college senior is convinced that he will be drafted. If he is not, then he is equally convinced that he will make an NBA team anyway as a free agent. In the meantime, he turns all offers down from international teams. Once the NBA season starts and he realizes that the NBA was just a dream, he finds himself without any options left. His market value has dropped to maybe half of what it was a couple of months earlier and some stay unemployed for the whole season. This is how the careers of talented college players end before they even start. When the NBA dream becomes an obsession.