The San Francisco 49ers hoped Yetur Gross-Matos would be a key part of their defensive line rotation when they signed him to a two-year contract in free agency.

But the 49ers will be without him for a crucial stretch of the season after he was placed on injured reserve on Saturday because of a knee injury.

Gross-Matos missed the season opener against the New York Jets with a knee problem before featuring in each of the last three games, showing intriguing upside rushing the passer from the interior as well as off the edge in the Week 4 win over the New England Patriots.

However, Gross-Matos missed every practice this week ahead of the Week 5 clash with the Arizona Cardinals and must now miss the next four games, a stretch that also includes matchups with the Seattle Seahawks, Kansas City Chiefs and Dallas Cowboys.

It is a string of games that could go a long way to defining the season for 2-2 San Francisco and Gross-Matos' absence robs the 49ers of some much-needed flexibility on the D-Line.

In a corresponding move, the 49ers activated defensive tackle Kalia Davis from injured reserve, giving them added depth on the interior that will now be even more important given the option of using Gross-Matos inside is not at the their disposal for the next four weeks.

Davis flashed some promise rushing the passer in his three appearances for the Niners last season and looked explosive in the preseason opener before requiring surgery on a knee injury. His return not only gives the Niners another interior rusher, but also provides them with a 310-pound body with which to hopefully clog running lanes for opponents. San Francisco has at best been up and down against the run this season.

On top of the return of Davis, the 49ers also elevated veteran defensive tackle T.Y. McGill from the practice squad, meaning San Francisco will be five deep up the middle against the Cardinals.

In addition, they also elevated wide receiver Trent Taylor for his first game for the 49ers since 2020. Veteran wideout Chris Conley is doubtful with an oblique injury and rookie receiver Jacob Cowing is questionable with a shoulder issue. Taylor is a candidate to serve as a return man for the 49ers in punt returner Cowing's potential absence.

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He has history in his sights.