Jerick McKinnon made his return to practice on Tuesday as the San Francisco 49ers running back continued his recovery from a torn ACL that kept him out all of the 2018 season. That positive momentum, however, was short-lived as Tom Pelissero of the NFL Network reports McKinnon suffered a "flare-up" in his surgically repaired knee during Tuesday's session. 

On Wednesday, 49ers general manager John Lynch then said things that were "not encouraging" surrounding McKinnon during an appearance on KNBR. 

"It's a real bummer because you keep getting to the final step and the final step is actually playing NFL football, and particularly at his position, where you have to make hard cuts, you have to put your foot in the ground, and we did it a month ago and we did it a month ago and he kind of regressed and I would say yesterday we had a similar situation," Lynch said, via "So we're trying to get to what's the root cause of the problem that he's having. And just because he's working through it, I'm going to leave it at that, but yesterday was not encouraging from that standpoint for Jet. What that means, we're not sure yet, but we're working hard to find that out."

This isn't the first time that McKinnon has suffered a setback on that knee as he was on the PUP (physically unable to perform) list to start training camp. When he returned to practice on August 6, he again aggravated that surgically repaired knee and now finds himself in a similar situation here. 

The 27-year-old signed a four-year, $30 million deal with the 49ers back in March of 2018, but hasn't been able to make an impact on the field yet in the Bay Area. Prior to landing with the Niners, McKinnon was a depth piece in Minnesota where he totaled 1,918 yards rushing and seven touchdowns to go along with 142 receptions for 984 yards and five more scores over four seasons. 

With this latest injury bug biting hard on McKinnon, San Francisco finds themselves in a bit of a bind. If they cut him, they'd have to eat $9.750 million in dead cap money in 2019, $4 million in 2020 and $2 million in 2021. 

As it relates to the upcoming 53-man roster decision, they'd had to put him on the opening roster if they wanted to place their back on short-term injured reserve with the potential to play this season. That, in turn, would result in the 49ers having one less roster spot for a healthier player. If they place him on IR before Saturday's deadline, McKinnon would be ruled out for all of 2019. 

The decision will need to be made by the 49ers brass as it relates to McKinnon, but luckily for the 49ers, they do boast one of the deeper backfields in the league with Matt Breida and Tevin Coleman headlining the unit. Preseason standout Raheem Mostert will now step into the No. 3 role.