Injury concerns surround the San Francisco 49ers as they prepare to face the Cincinnati Bengals in Week 8. The team is grappling with several key players likely to be sidelined for the upcoming game.

On Wednesday, quarterback Brock Purdy entered the concussion protocol, adding to the injury woes. Wide receiver Deebo Samuel had already been ruled out with a shoulder injury, while left tackle Trent Williams missed practice on Wednesday after sitting out Week 7 against the Minnesota Vikings due to an ankle injury.

Head coach Kyle Shanahan expressed optimism that Williams could return to practice on Thursday and potentially play against the Bengals. However, if Williams does make an appearance, he will be protecting Sam Darnold, raising questions about the fantasy football prospects for the 49ers.

Despite the uncertainties, star running back Christian McCaffrey remains a must-start fantasy option in all leagues, as he is unaffected by Darnold's presence. McCaffrey's performance is crucial to the 49ers' success and fantasy owners can rest assured that he will continue to produce.

In addition, wide receiver Brandon Aiyuk and tight end George Kittle are expected to thrive with Darnold under center. Kittle, who has performed exceptionally well in the absence of Aiyuk or Samuel in the past, should be a top choice among tight ends. He showcased his abilities with 16 PPR points in Week 3 against the Giants when Aiyuk was unavailable and 13 PPR points in Week 7 at Minnesota with Samuel sidelined.

The Bengals defense has struggled against tight ends, allowing three to score at least 10.6 PPR points this season. Kittle presents immense upside and should be considered a top-five option at his position, even with Darnold's involvement.

On the other hand, Aiyuk's performance is more uncertain. He has scored 11.6 PPR points or less in the last three games against Dallas, Cleveland, and Minnesota. In the absence of Samuel against the Vikings, Aiyuk managed just five catches for 57 yards on six targets. Moreover, he has not scored a touchdown since Week 1.

The Bengals secondary has proven to be formidable, with only one No. 1 receiver finding the end zone against them so far this season. Aiyuk may face challenges in having a standout performance against them. Despite this, he remains a borderline starter in all leagues and a definite starter in three-receiver leagues. Fantasy managers should not downgrade Aiyuk solely based on the quarterback change.

Coach Shanahan is expected to maximize Darnold's potential, aiming to bring out the best in McCaffrey, Aiyuk, and Kittle. The absence of Purdy is expected to have minimal impact on the key 49ers players, especially if Williams can reclaim his spot on the offensive line.

As fantasy football enthusiasts prepare for Week 8, they will closely monitor the injury updates surrounding the 49ers and make informed decisions about their lineups. The game against the Bengals poses both challenges and opportunities for the San Francisco players, and the performance of McCaffrey, Aiyuk, and Kittle will undoubtedly attract significant attention.