There are many advocates for minor league baseball players to get paid more money. I can't say that I disagree. There are a number of young adults working the minor leagues for minimum wage or less and I don't just mean the hot dog vendors.
But if MLB ever wants to look at fixing this, there might be value in looking at the signing bonus pools to find revenue to redistribute. Obviously those at the higher end of the pool are receiving life changing money and probably not concerned about the measly annual salary they receive in the minor leagues. Even over $800,000 signing bonus for the third pick is a lot of cash. If you average that out over five years in the minors that player is making over $160,000 per year. Pretty good bones for an 18 - 22 year old without much employment history.
But lets look further down the pay scale at the 10th pick with a suggested slot level bonus of $138,000 for signing. That would break out to $27,600 a year for a five year minor league career plus what ever annual salary the player may receive. Considering that the season is at the most eight months a year that comes down to $3,750 a month or about $144 a day for a six day work week or $14.40 an hour for 10 hours a day for 6 days a week. Not outstanding pay but better than McDonalds and your whole workplace experience is training for a future job where you can make millions. Most 20 year olds would accept that.
So the bigger issue is for folks that do not get the signing bonus either because they sign for under slot or they are picked in the 34th round at take a chance on their major league dream or just one more summer playing the game in the sun.
It may make sense to redistribute some of the higher signing bonuses down to make sure every minor league player receives a living wage. Even if you just lower the top signing bonuses amount by a total of $1M that would provide $10K per player per year for those that didn't receive a signing bonus over $100,000. (The Math*: 150 players in the system - 50 (10 a year) that received a signing bonus of $100,000 = 100 players $1,000,000/100 players = $10,000 per player.
Instead of providing a flat amount per player, MLB could stratify these amounts to reward longevity or folks in the upper minors. Year 1: $6,000/yr Year 2: $8,000/yr Year 3: $10,000/yr Year 4: $12,000/yr Year 5 and beyond $14,000/yr.
So simply by taking $1M off the signing bonus pool designated for the top 3 players on each team, there could be a significant change in minor league pay. This solution may be more likely than trying to get major league players to take less in order to improve the pay for minor leaguers.
* Math is provided to show potential scenarios and is based upon well thought out and researched assumptions. Actual amounts may vary slightly.