SANTA CLARA, Calif. -- For the San Francisco 49ers to contend for the playoffs this season, here are five players who are integral in making that happen:

Jimmy Garoppolo, quarterback: It's not exactly breaking news to say that the play of the starting quarterback is going to go a long way in determining a team's fate. But in the Niners' case, Garoppolo takes on even more importance. San Francisco was 1-10 when Garoppolo became the starter in 2017 and won the final five games of the year with him under center, including victories against playoff-bound teams like Jacksonville and Tennessee. Garoppolo's impact on the team was immediate and far-reaching and he did all of it despite having little time to learn coach Kyle Shanahan's offense after three-and-a-half years in New England. Garoppolo still has some proving to do as he enters his first full season as a starter, but given the Niners' investments in bolstering his supporting cast and a full offseason to dive into Shanahan's playbook, he has a chance to make the 49ers legitimate playoff contenders.

Richard Sherman, cornerback: Signed to offer help at corner and provide veteran guidance to a young secondary, Sherman is coming off of a serious injury for the first time in his seven seasons. That Achilles injury left questions about whether the 30-year-old Sherman can return to his status as one of the league's top cornerbacks. For the Niners to make the leap to the postseason, they'll need Sherman to at least approximate his previous All Pro form while also serving as the mentor for young defensive backs like Ahkello Witherspoon and Adrian Colbert.

Joe Staley, left tackle: If Garoppolo is the biggest key to the Niners having success in 2018, keeping him upright is one of the team's top priorities. For the 12th consecutive year, protecting the Niners' quarterback will fall largely in the hands of Staley. Staley will turn 34 at the end of August but is coming off another good season. The 49ers began planning for life without Staley when they drafted Mike McGlinchey with the No. 9 pick in April. McGlinchey is expected to take over on the right side this year but the Niners will need yet another strong year from Staley, who doubles as a key locker room leader and will be critical in continuing to build the culture Shanahan seeks.

Solomon Thomas, defensive lineman: Aside from taking a flyer on Jerry Attaochu, the Niners didn't address what was arguably their biggest offseason need: help at edge-rusher. Which means they will once again move forward with what they already have in place. It also means they will probably have at least one defensive lineman playing a position that's not his ideal fit. As it stands, Thomas looks to be the most likely to do that. With Arik Armstead expected to move to the "big" end spot, and DeForest Buckner entrenched as the three-technique defensive tackle, Thomas will have to play early downs as the "Leo" defensive end. That position is generally reserved for the best outside pass-rusher but Thomas might have to handle it, at least on running downs. Ideally, he can move inside in obvious passing situations. Either way, the 49ers will look for more from him in getting after the quarterback in 2018 after a rookie year in which he finished with three sacks.

Jerick McKinnon, running back: In one of the most eye-opening deals of free agency, the 49ers gave McKinnon a four-year, $30 million deal that pays him up to $12 million in the first year. That deal surprised many given that McKinnon had never emerged as the primary back during his time with the Minnesota Vikings. But Shanahan viewed McKinnon as the ideal fit in his offense and a potential game-changer as a runner and a pass-catcher. McKinnon is easily the most accomplished back on the roster and if he can succeed in a larger role than he's ever filled before, it would be instrumental in getting the 49ers back to the NFL's Promised Land.