Commercial obligations are written into playing contracts in hours, and those hours come from somewhere real.
Sponsor appearance days are paid for out of training time
Count the days. A typical top-flight contract obliges a player to a set number of commercial appearances per season, plus media duties, plus club content shoots that nobody counts because they happen at the training ground. Ten or fifteen days across a year sounds trivial. It is not, because of when they land.
Commercial partners want access at the moments that suit their campaigns: pre-season, the week of a marquee fixture, the run-up to a shirt launch. Those are precisely the weeks a coaching staff has planned most carefully. A morning shoot moves a session to the afternoon, or removes it. Tour schedules are the extreme case, where a squad flies to three cities in ten days because a sponsor bought market activation, and the preparation the coach wanted becomes a series of airports.
Clubs will tell you the money funds the squad, and it does. Sponsorship and matchday revenue are what pay wages at almost every level below the very top. The uncomfortable part is that the cost is borne in a currency nobody measures. There is no line in the accounts for training hours surrendered, no reporting requirement, and no internal owner of the number.
I would give it one. A single register, kept by the performance department, recording every hour of player time taken by commercial activity, reported to the board alongside the revenue it generated. Not to stop it. To price it.
The moment you do that, some deals look different. A regional partner paying modestly for four appearance days in the busiest month of the calendar is not obviously a good trade, and a commercial team with a target to hit has no reason to notice. Deals should be assessed on revenue per hour of player time, the same way any other business assesses a constrained resource.
Player associations have pushed on this in a few sports, mostly framed as welfare, which is fair but weaker than the business case.
The business case is simply this: attention is the scarce input, and clubs currently sell it at whatever price the commercial department can get, without anyone checking what it cost the team.

