As part of MLB's health and safety protocols during the COVID-19 pandemic, all half-innings after the ninth will begin with a runner on second base in the 2020 regular season. This rule will not be in place for the 2020 postseason or the 2021 campaign.
The runner placed on second base at the start of each half-inning in extras will be the player in the batting order immediately preceding that half-inning's leadoff hitter, or a pinch-runner. So, if the No. 7 hitter in the order is due to lead off, the No. 6 hitter (or a pinch-runner for the No. 6 hitter) would be placed on second base.
If the automatic runner comes around to score, an earned run will not be charged to the pitcher.