The San Francisco 49ers are looking to return to contention after a brutal 2024 collapse from Super Bowl runners-up to a last-place finish in the NFC West, a season marred by injuries and mediocre play.Multiple changes occurred during the lull. Many players left, headlined by dual-threat wide receiver Deebo Samuel, who was traded to the Washington Commanders. Klay Kubiak was hired as offensive coordinator, Robert Saleh returned to handle the defense, and Brant Boyer was put in charge of special teams.The team opens its season Sunday with an intradivision matchup against the Seattle Seahawks, and there are some updates concerning key players.San Francisco 49ers Fantasy Football Injury Update Week 1Christian McCaffrey injury updateSeattle Seahawks v San Francisco 49ers - Source: GettyThe 49ers' offensive dynamo is expected to be back, as Christian McCaffrey has successfully overcome his hamstring and knee injuries. During a press conference last month, head coach Kyle Shanahan said:“I think he hit like 25 (MPH) yesterday or something like that. I’m just making that up. Trying to make Christian happy. He’s doing awesome. He’s as fast as he’s been. He’s quick. He’s strong.”Should he either be injured again or struggle, McCaffrey need not worry, as the franchise traded for Brian Robinson a day after the preseason ended. The ex-Commander will be joined by sophomore Isaac Guerendo and fifth-round rookie Jordan James, forming a solid core behind the former Offensive Player of the Year.Jauan Jennings injury updateChicago Bears v San Francisco 49ers - Source: GettyAfter spending his early career mainly as a backup, Jauan Jennings broke out in 2024, becoming a primary starter for the first time and setting career highs in every relevant category. Only an ejection during the season finale against the Arizona Cardinals prevented him from joining the 1,000-yard club.He had been dealing with a calf injury throughout the preseason but participated in the 49ers’ special practice session Monday. That also represents good news for contract negotiations between him and the organization, as he had requested a trade entering the final year of his current deal, according to general manager John Lynch.Jennings is expected to line up beside Brandon Aiyuk, who is making his comeback from a knee injury that ended his 2024 campaign after just seven games. Ricky Pearsall and Skyy Moore are potential substitutes should he be injured again.Other 49ers injury updatesAlso back on the field on Monday were the following:WR Russell Gage Jr. (knee) (released on Tuesday)G Dominick Puni (knee)DT Kalia Davis (leg)DE Yetur Gross-Matos (knee)CB Upton Stout (calf)The only player who did not take the field was rookie wideout Jordan Watkins (ankle).