The 49ers have had a disappointing fantasy season, although continued injuries (and last week's weather) haven't helped. Fantasy managers must remain patient waiting for Trey Lance, who returned to practice this week and could see some snaps Sunday. Since facing Detroit's league-worst secondary in Week 1, Jimmy Garoppolo has gotten just 6.6 YPA with a 5:4 TD:INT ratio over four games. Playing in a monsoon contributed last week, but Jimmy G is coming off one of the worst games of his career.
Deebo Samuel is the No. 2 fantasy receiver this year. Assuming Samuel is good to go after missing practice time with a calf issue, he remains a must fantasy start as the NFL's leader in target share (and in yards after the catch despite SF already having its Bye). The Bears have allowed the fourth-most fantasy points to wide receivers this season.
Chicago is easier to run against (No. 17 in DVOA) than pass (No. 7), and is dealing with injuries to Khalil Mack (out), Akiem Hicks and Robert Quinn along its defensive line. Elijah Mitchell was second among all running backs in carry percentage last week, so he's being treated like San Francisco's true feature back on non-third downs. He's been coming off the field during all passing situations, limiting his fantasy upside, but Mitchell is a top-15 RB this week anyway. With game-script possibly being in his favor against a banged-up Chicago front, Mitchell has the potential to have a big game rushing Sunday (Trent Williams returning would help).
Over five starts, Justin Fields has taken 20 sacks, thrown five interceptions, fumbled five times and thrown just two touchdowns. The 49ers have allowed just 6.8 YPA yet have recorded only one pick all season, which certainly seems unlucky (although a disappointingly low pressure rate has contributed). The Bears have three-total passing touchdowns this season, so it's possible SF isn't flagged for a half-dozen long PI penalties this week too. Therefore, the 49ers are my top fantasy defense in Week 8.
While no other Bears player can be trusted in fantasy lineups (and Allen Robinson can be dropped, sadly), the highly impressive Khalil Herbert is a top-20 RB this week. The rookie dominated touches over Damien Williams last week and somehow rushed for 100 yards (5.6 YPC) on the road against a Tampa Bay defense allowing an NFL-low 51.3 rushing yards per game to running backs this season. It's unclear what happens once David Montgomery returns, but Herbert is a strong fantasy start in the meantime.
Dalton Del Don has been with Yahoo! Sports since 2013, covering fantasy football, baseball and basketball. He appears on multiple podcasts each week and currently resides in the Bay Area, where he is an avid fan of the Golden State Warriors and 49ers.