There are various occasions in which we have seen managers turn to their sub keeper as an outfield player out of necessity.
In others, it has been done for pleasure, as in this Maharlika v Mendiola from the Philippines League, where the visiting team put their substitute goalkeeper on as a striker in added time of the second half.
One wrong move, one open opportunity.
Mendiola's attacking force takes a fast chance after a poor touch from Basa and steals a team effort goal, putting them way ahead of Maharlika now.
— 1 Play Sports (@1playsports) November 9, 2020
It happened in the Philippines League. Mendiola, who if they won would secure 4th place and therefore the chance to play in continental competition next season, put their sub keeper on as a striker to waste time in added time of the second half.
Mendiola were winning 2-0 against Maharlika, their opponent for 4th place, and then in the 92nd minute something that isn’t often seen happened, at least without needing to.
Mendiola had scored the goal to finish the match (Flores in the 90th), and their manager made the last change in added time. An outfield player came off for their sub keeper.
— Philippines Football League (@WeArePFL) November 9, 2020
Effectively, Kenry Balobo replaced Stephen Appiah and played the last few seconds of the match. It was their third and final change, and they didn’t do so because they needed to, as they had two other players on the bench (they could have put Malayo or Balabat on because they came into the match with just 5 subs).