The San Francisco 49ers are facing the Arizona Cardinals in a Week 1 matchup of NFC West foes. George Kittle has already been in and out of this game.

According to Adam Schefter of ESPN on Twitter and Cam Inman of mercurynews.com, superstar tight end George Kittle suffered a knee injury and left the game before halftime.

Kittle has quickly established himself as one of the very best tight ends in all of football. And he is very clearly one of the most important pieces in the San Francisco offense.

Due to that, this is a pretty massive blow. And going up against a revamped and exciting Arizona team, the 49ers probably couldn't afford this type of an injury.

There is some good news though. According to Darren Urban of azcardinals.com on Twitter, Kittle returned in the third quarter.

Kittle finished 2019 with 85 receptions for 1,053 yards and five touchdowns. Most impressively, he did that in just 14 games.

So it is pretty obvious why many consider him right at the top of the “elite” tight end list.

It's also obvious how much losing Kittle could hurt the 49ers, a team more known for defense and running than passing.

Entering the fourth quarter, the 49ers find themselves up just 13-10 over the Cardinals. They will need to get their offense going a little bit if they plan on walking away from Week 1 with a W.

That means Kittle will likely be featured pretty heavily. So hopefully everything is fine with his knee and it holds up for the rest of the game. While it would be disappointing for them to lose the game, it would be much worse for Kittle to suffer any type of injury that will keep him out of action for multiple weeks.

So San Francisco is likely monitoring the knee and making sure Kittle is staying healthy. Don't be surprised if he makes a big play in the fourth quarter to help his team though, even on a wobbled leg.