Three days after being activated from the physically unable to perform list, San Francisco 49ers running back Jerick McKinnon faces another obstacle in his comeback from knee surgery.After returning to practice on Tuesday, McKinnon will be shut down for at least two weeks and receive platelet-rich plasma injection treatment on his ailing right knee. McKinnon experienced unusual soreness as he ramped up activity at 49ers training camp.According to reports, placing McKinnon on injured reserve to start the season is under consideration. Running backs Tevin Coleman and Matt Breida could split the workload with McKinnon out.McKinnon, 27, missed the entire 2018 season after tearing the ACL in his right knee in practice at the beginning of September.”11 months 5 days let’s get back to what we do now!” he tweeted on Monday.McKinnon signed a four-year, $30 million contract (with $18 million guaranteed) with San Francisco in March 2018 after four seasons with the Minnesota Vikings.The 2014 third-round pick rushed for 1,918 yards and seven touchdowns and caught 142 passes for 984 yards and five scores in 58 games with the Vikings.
