The 49ers earned a win in Week 9 but they may have suffered yet another major injury on defense along the way. Mykel Williams‘ rookie campaign may be over. 
Head coach Kyle Shanahan said (via Cam Inman of the San Jose Mercury News) the team fears Williams suffered an ACL tear in today’s win against the Giants. The first-rounder went down with roughly four minutes remaining in the fourth quarter of today’s game, and a season-ending absence could now be in store.
Further testing – including an MRI – will take place to confirm a diagnosis. When coaches express concern about major injuries such as this, however, it is rare the worst-case scenario winds up being avoided. If that holds true for Williams, San Francisco’s pass rush will be even further shorthanded for the second half of the campaign.
The team is already without Nick Bosa, who suffered an ACL tear of his own in September. Since then, linebacker Fred Warner has gone down with an ankle injury which threatens to keep him sidelined for the rest of the season. If Williams – who has served as a full-time starter during his rookie campaign – is indeed out for the stretch run and the playoffs, the 49ers could be forced to an even larger extent to add a pass rusher ahead of the trade deadline.
The team has been connected to making at least one acquisition in that regard, with links emerging to Trey Hendrickson in particular. A blockbuster along those lines would be a surprise, but San Francisco was already among the teams to watch on the trade front for an EDGE addition prior to today. That will especially be the case if Williams is sidelined.
The 21-year-old notched just one sack and three QB pressures during his first eight appearances. Williams nevertheless logged a 68% snap share, and that was set to continue (particularly while Bryce Huff recovers from a hamstring ailment). The 49ers have the cap space to afford a rental trade addition and at 6-3 they could easily adopt a buyer’s stance leading up to the November 4 deadline. Out of necessity, a move could be in store shortly.