The San Francisco 49ers have announced that the team has officially placed Dre Greenlaw on injured reserve. The linebacker had core muscle surgery this week and is expected to miss about four to six weeks.
"Dre, I think it's his oblique, is what you would call it," Shanahan said on Friday. "That's been bothering him for a little bit. It's something that sometimes gets better the more you rest it. That's why we've been careful with him in practice and everything. But as you do that, as we've been doing for a few weeks, and it's still getting worse, that means you know it's not going to heal up.
"So we finally had to make that decision yesterday, which was a tough decision because of how good of a player Dre is for us, but we could just tell it wasn't going to heal. With it being this early in the year, not something we want to hesitate on. So hopefully, this surgery will go well, and he'll be back sooner than later."
San Francisco made Greenlaw (6-0, 227) a fifth-round selection out of Arkansas in 2019. He registered six tackles, a pass defensed, an interception, and a touchdown in the 49ers' Week 1 victory over the Detroit Lions.
"We're expecting Dre in four to six weeks, and if there isn't anything that goes bad, I'd be pretty confident in that happening," added Shanahan.
Greenlaw, 24, has recorded 184 tackles, two sacks, four passes defensed, two interceptions, and a touchdown in 30 game appearances (23 starts) through his three NFL seasons.