The 49ers’ disappointing 5-11 finish in 2020 can be chalked up to a host of issues. While they retained a number of key free agents and appear poised to once again contend in a very good NFC West, it’s going to take a slew of bounce-back performances from players who lacked last season.

Many of the players in need of a better year in 2021 can chalk up disappointing 2020s to injury. For some it’ll be as simple as playing a full year. For others it’ll require a step up in production. There are a number of players who’ll need to do both on some level.

Here are six 49ers in need of bounce-back years in 2021:

DE Nick Bosa

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A torn ACL in Week 2 cut Bosa’s sophomore campaign short. His success is the biggest key for San Francisco’s defense this year. The 49ers need him not only to be healthy, but to build on his strong rookie season where he had 9.0 sacks and 85 quarterback pressures.

RB Raheem Mostert

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Mostert was tracking for his most all-around productive year last year before a series of injuries wound up limiting him to only eight games. He averaged 5.0 yards per carry, which is excellent, but below the bar he set in 2018 and 2019. The 49ers will need him to continue averaging in the 5.0 YPC range while racking up 180-200 carries across a full season of work. His explosiveness makes him a threat to score every time he touches the ball and his ability to generate big plays on the ground help elevate San Francisco’s offense to a level it can’t reach without him.

QB Jimmy Garoppolo

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Health was a huge problem for Garoppolo last year, but even when he played he wasn’t exceptional. His decision-making wasn’t great and his accuracy saw a dip as well. Not only does he need to play well to hold onto his starting job ahead of Trey Lance, he’ll have to be good to put the 49ers in a position to reach the postseason again no matter how many games he starts.

SS Jaquiski Tartt

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Tartt played in only eight games last year and re-signed with the 49ers on a one-year deal this offseason. He wasn’t a lock to start, but Tarvarius Moore’s torn Achilles pushes Tartt up the depth chart and likely into a starting role. He was very good in 2019, and regaining that form while staying available for the whole season would buoy a relatively thin 49ers secondary.

RT Mike McGlinchey

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Injuries weren’t a problem for McGlinchey in 2021. In fact, he started all 16 games and he was still a good run blocker. Pass protection was a significant issue for the 49ers’ right tackle last season though. It’s never been the former first-round pick’s strength, but there were enough lapses last year that it raised questions about his long-term viability as a starter. San Francisco’s offense will be in a better spot if he returns to form and sees an uptick in productivity as a pass blocker in 2021.

CB K'Waun Williams

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Williams is another player who’s 2020 was truncated by injury. In his eight games though Williams went without an interception and forced only one fumble. He’s still one of the better slot defenders in the league, but he’s at his most impactful when he’s generating turnovers. Getting him on the field is important, but he can dramatically alter the 49ers’ defense by staying around the ball and picking up the turnover productivity this season.