How do sportsbooks set player prop lines?
Short answer: Books open player prop lines from a projection of the player's minutes and usage, often bought from data providers, then adjust toward the prices at sharper market-making books and move again on bets and injury news. Books update at different speeds, so the same prop can sit at different prices across books.
Step 1: a projection
Books start from a projection of the player's output: minutes, usage, pace, the opponent, recent form and injuries around him. Many books buy these numbers from data providers rather than build them in-house, which is one reason opening lines look similar across books.
Step 2: the market
After opening, most retail books watch where the sharper market-making books price the same prop and adjust toward it. Pinnacle, which takes large bets from professionals and moves on that money, is the usual reference (what a market-maker book is).
Step 3: money and news
Lines then move on bets taken and on news: a teammate ruled out, a starter returning, a minutes restriction. Injury news is the biggest single mover on props (how injury reports move prop lines). Books also limit how much they take on props, which keeps the market thinner than main lines.
Why this creates price differences
Because books update at different speeds and with different inputs, the same prop can sit at different prices for minutes or hours. Those gaps are what OpenSlate measures every hour, DraftKings against Pinnacle, on the free props page.
Opening versus closing lines
The opening line is the book's first estimate; the closing line is the last price before the game starts, after hours of bets and news. Closing lines are usually more accurate, because they include more information. That is why bettors compare the price they got with the close (closing line value), and why a line that has not moved all day at one book while others have is worth a second look.
Why limits are low on props
Props are numerous and individually small, so a book cannot afford to research each one as deeply as a point spread. Low betting limits are how books manage that risk: they cap how much any one bettor can win before the line gets corrected. Limits usually rise closer to the start, once lineups are confirmed and the price has absorbed more money.
What this means when you compare prices
Because books move at different speeds, a gap between two books is often just one of them being slow. Gaps right after news tend to close fast; gaps that persist for hours usually reflect a real difference of opinion between the books' models.
Related questions
- Why do DraftKings and Pinnacle prop lines differ?
- How often do prop lines move before tip-off?
- What is a steam move?
Market data and education only. OpenSlate does not publish free picks and does not tell you what to bet.
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