This means the Ravens lose the franchise's all-time leader in sacks as well as their emotional leader.
"That's our leader. The motto here is next man up, and you're going to hear everybody saying that," Upshaw said. "But you never want to lose a guy like him. He's been a cornerstone for this defense for a long time."
This will lead to speculation whether Suggs has played his last game. He turns 33 next month, and he acknowledged this summer that he's on the "back nine" of his career.
It marks the second time that Suggs has torn an Achilles in the past 40 months. He tore his right Achilles in the spring of 2012, and he injured his left one in the middle of the fourth quarter Sunday.
In the season opener, Suggs walked off on his own, which caused many teammates to think he had just cramped up. Suggs also didn't want to get carted off to the locker room, but the doctors insisted.
Suggs has 106.5 career sacks, which is 36 more than any other Ravens player. He has the sixth-most sacks among active players.
"Here's a tough, tough break for a guy who's done nothing but work above and beyond to a degree and be the kind of leader that you just admire so much," coach John Harbaugh said. "These are the things in life that happen. Adversity is how you respond to it. It's about how you react to it. It's about how you come back and play the next game, and how our young guys step up and how our older guys wrap their wings around those young guys."
Suggs took to Twitter with some positive words for the fans.
The injury to Suggs is compounded by the loss of Pernell McPhee in free agency. Suggs and McPhee accounted for 19.5 sacks last season.
Za'Darius Smith is listed as Suggs' backup on the depth chart, but the rookie fourth-round pick was inactive on Sunday. Baltimore could look to add a veteran pass-rusher like Dwight Freeney.
"You can never replace Terrell Suggs," linebacker Elvis Dumervil said. "It hurts everybody when you hear news like that."