Why do most manager only use relievers for a single inning? Assuming that a reliever is not a LOOGY (and the Rangers have none of those at the moment), why don't all reliever get used for two innings at a time? Assuming the innings pitched by your starters remains fixed, allowing your relievers to go two innings doesn't increase their load, it just distributes it differently. Relievers would pitch two innings, then get an extra day of rest. Has this been shown to adversely affect health or performance? Most relievers are capable of going more than one inning. They are not relievers because they don't have the stamina to pitch two innings. They are reliever because they didn't have the repertoire to go through a batting order multiple times. Pitching two innings would mean that they only face each batter one time, unless they are getting smacked around, in which case they would be pulled anyway. What am I missing? An obvious answer is related to match ups (LHP vs LHB, etc), but how often do you look at the box scores, most of the time, the relievers are coming in when the starter is done, they go one inning, then the next reliever comes in for an inning. This is especially true in the AL. In the NL, relievers tend to come in when the pitcher's slot in the order comes up.