RB (Run Line)

The run line is baseball's version of the point spread, and it is almost always fixed at one and a half runs rather than varying from game to game. Because baseball matches are typically decided by far fewer runs than the points in football or basketball, a single standardised 1.5-run line does the job that a fluctuating spread does in higher-scoring sports. The structure is symmetrical. The favourite is listed at -1.5 and must win by two runs or more; the underdog at +1.5 wins the bet either by winning outright or by losing by a single run. A favourite that wins 3-2 fails on the run line because the one-run margin falls short of the required two, even though they won the game. Its main use is to reshape the price on lopsided matchups. Backing a heavy favourite on the moneyline might offer very short odds, but taking that same favourite at -1.5 lengthens the price towards even money in exchange for the two-run requirement. Conversely, an underdog at +1.5 trades shorter odds for the cushion of being able to lose narrowly and still win. The common mistake is treating -1.5 as a near-certainty for a strong team and ignoring how often baseball games are decided by exactly one run. A large share of matches finish within a single run, so favourites frequently win the game yet fail to cover the run line. Weighing the real frequency of one-run results against the improved odds is the key to using the run line sensibly rather than assuming a good team will simply win comfortably.