Christian McCaffrey is a touchdown-scoring machine, and sportsbooks don’t want you cashing in on his uncanny ability to reach the end zone.

The star 49ers running back can be had at -500 on BetRivers Sportsbook to score a touchdown in Saturday night’s NFL playoff matchup with the Packers.

McCaffrey scored a league-best 21 touchdowns this season, 14 of them being rushing scores.

But odds like these have been normal for much of the season; McCaffrey scored in 17 straight games dating back to last season and hasn’t been plus-money to score a touchdown this season.

Before his 17th game with a score, The Post pointed out that you’d be up $480,991.48 if you had rolled over a $100 bet on McCaffrey to score in the previous games.

The odds have continued to go higher but, oddly enough, with touchdown scorers the betting odds are rarely indicative of the actual price of a player actually getting into the end zone.

McCaffrey’s -500 odds seem extremely wide to get into the end zone — implied odds are 83.33 percent he scores – but you also cannot bet “no” or “McCaffrey not to score a touchdown” at the opposite price (fair value roughly +350 given -500 odds on yes).

If you could, it’s a fair expectation that McCaffrey would not score a touchdown and would be bet down to +250 at the most.

ESPN BET has the option available for all players and, wouldn’t you know it, they have the best price on McCaffrey to score a touchdown on Saturday across all sportsbooks.

This is a small but significant difference that ESPN BET is offering over some competitors. The option to bet “no” gives you the true price – although ESPN is charging a 7.81 percent vig on the market.

The difference between -275 and -500 is the difference between a $20 payout on a $100 bet or $36.36 profit.

Always line shop, and look to bet “no” or “under” when possible.

McCaffrey and the top-seeded 49ers are 9.5-point favorites at FanDuel against the seventh-seeded 49ers for Saturday’s matchup in Santa Clara, Calif.