The San Francisco 49ers likely didn't envision their poor start against the Arizona Cardinals on Thursday. After the Kyler Murray-led Redbirds marched their ways down the field for a touchdown, the 49ers suffered a big blow to their offense when George Kittle went down with a knee injury early into their first-drive.

Kittle took a blow to the knee from the helmet of a Cardinals defender. According to Matt Barrows of The Athletic, he quickly went into the blue medical tent for inspection. The 49ers have Ross Dwelley and Levine Toilolo as their backups.

Kittle does not have a past with knee injuries. In terms of lower-body injuries, he has suffered a pedal foot sprain (college), a thigh hamstring pull and pedal ankle sprain, according to Sports Injury Predictor.

Kittle eventually left the tent and re-inserted himself back in the lineup. On the first snap coming back from the injury, the 49ers ran right to his side. It appears he will be fine for the rest of the game. He looked a little slow in his movements and cuts at times, but got better as the first half went along and was able to get open versus Arizona's coverages.

The third-year tight end is an integral piece to the 49ers' offense and is a catalyst for their 2019 success. On the year, Kittle has 40 receptions for 462 yards and a touchdown. He is also considered to be one of the NFL's best run-blockers and tends to epitomize what it means to play the position.

In 2018, as a second-year unknown, Kittle broke the NFL regular-season record for receiving yards by a tight end (1,377). It's fair to say that San Francisco's passing offense depends on his availability.