The San Francisco 49ers on Sunday officially announced the trade for running back Brian Robinson. Their official roster move shed light on why the club waited until after the preseason finale to announce the trade.

There weren’t any surprises in the official announcement with a 2026 sixth-round pick going to the Commanders in the swap. To make room on the 90-man roster the 49ers waived wide receiver Malik Knowles.

Knowles joined the club multiple times during the offseason, most recently on Aug. 20 to help them get through the final week of the preseason.

San Francisco’s injury situation was such that they needed to wait until after they got through their preseason finale to make the move official. Once they announced the trade they’d have to get rid of a player on their 90-man roster, even if Robinson wasn’t going to suit up in Saturday’s matchup with the Los Angeles Chargers.

Instead, the 49ers got through their game where Knowles only wound up playing one snap on special teams. Going into the contest even one player short could have been disastrous for a roster that’s been pummeled by injuries throughout the preseason.

The move leaves the 49ers at the maximum 90 players heading into the couple of days leading up to final cuts. San Francisco must trim its roster to 53 players by 1:00pm Pacific Time on Tuesday.

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This article originally appeared on Niners Wire: Brian Robinson trade announced by 49ers, WR Malik Knowles released