Commanders head coach Ron Rivera confirmed the decision on Wednesday as they re-shuffle the QB deck for one final time.
Wentz, in his first start after almost two months out with a fractured finger, completed 16 of 28 passes for 143 yards with three interceptions.
"I think first, initially, is obviously, it would be his first start, and it would become a little bit of a circus, having to deal with all of the things that come with being a starter, but also, you look at the opponent, and who you're playing and what they're playing for," Rivera told reporters.
"Going with Taylor would have given us an opportunity to see what they're doing, how they're doing it and would have given Sam a chance to look at it if we had gone with Taylor.
"At the end of the day, at some point, if Sam ever gets an opportunity to be a starter, this would be the chance. Why not get it over with now and go from there?
"The most important thing is that we're really intrigued in terms of watching and seeing what Sam can do as a quarterback in this league."
Wentz, 30, has two years remaining on his Washington contract, having joined via trade last offseason from the Indianapolis Colts.