2021 美國大聯盟規則，已將6.01(a)(1)增訂：
If a pitch that is not caught remains in the vicinity of home plate and it is
inadvertently deflected by the batter or umpire, that ball is a dead ball and
the runners should return to the bases they occupied at the time of the pitch
(but if the pitch was strike three, the batter is out).
捕手沒有接到的球，在本壘區附近，反彈到打者或主審，
在不經意的情況下，造成球的偏轉滾遠，裁判應立即宣告比賽停止球，
壘上跑壘員必須返回投手投球前所佔之壘。(若符合不死三振時，打者直接出局。)
以前原本是: 非故意的話比賽進行中，故意的話才是防礙守備。
範例詳見蘇建文的po文:
https://bit.ly/3ICmxNB