It depends.
If you are being a professional golfer to make a profit as an intent, that is a business. IRS considers you as a self-employed. You will need to file a Schedule C and you can deduct your expenses against your income.
However, if you are doing this as a hobby, which is defined as activities not to make a profit. You won't be able to deduct. Instead of a Schedule C, you are required to report the income as other income on line 21 of the Form 1040. With the new tax reform TCJA, you cannot deduct it against your income because they suspended the entire section of the Miscellaneous deductions subject to 2% of the AGI.
A hobby is defined as an activity that you engage in not to make a
profit. Even if you earn occasional income from doing such an activity,
the primary purpose must be something other than making a profit eg. sport or
recreational. A key feature of a business is
that people do it to make a profit.
To see if this is a hobby or business, click here https://www.irs.gov/newsroom/hobby-or-business-irs-offers-tips-to-decide
