The San Francisco 49ers had to fight off a battling Arizona Cardinals in order to get their Week 9 win. However, the team is hoping that they won't play the remainder of the season without outside linebacker Kwon Alexander.

Alexander was one of the casualties during the 49ers' narrow win as he suffered a chest injury. However, what has made Matt Maiocco and many observers worried was the nature of how he was deemed out immediately after getting hurt.

In remains to be seen how serious Alexander's injury is. Kyle Shanahan has confirmed that they will be getting an MRI on Alexander's chest to know the full scope of the injury.

This injury is a huge blow for the 49ers as they stuttered a bit on defense without him. The Cardinals actually got as close as three points in their daring comeback. Fortunately for them, the Niners defense managed to pull through and sneak out a close 28-25 triumph to remain undefeated on the season.

The offense also stepped up and made up for Alexander's absence. The running game was there, but the team's passing was the star of the night. Jimmy Garoppolo threw for 317 passing yards and four touchdowns. They did just enough to get them over the Kyler Murray-led Cardinals.

The 25-year-old Alexander is a key man for the San Francisco defense and will be missed if he is out for weeks. He's made 34 tackles, one interception, four pass deflections, and half a sack in his first season with the team.