Bath prop Beno Obano could be sidelined for a year after being injured during an England training camp.
The 23-year-old's club confirmed he suffered "multiple ligament and hamstring tendon damage" while attending the camp in Brighton last week.
Bath rugby director Todd Blackadder said: "While this type of injury is complex and can lead to a 12 month lay-off, we are investing in our medical team over the off-season and we are focused on getting Beno back as soon as possible."
Uncapped Obano's latest knee problem comes after a similar injury he suffered in January put an end to his NatWest 6 Nations hopes.
He had been set to play a role in the non-cap international against the Barbarians at Twickenham on Sunday, most likely as bench support for Joe Marler.
"Beno went for a scan this week, and after consulting with the specialist will undergo surgery to help repair his injury," Blackadder said.
"This will then be followed by a lengthy spell of rehabilitation.
"We are all feeling Beno's disappointment. It has been a breakthrough season for him.
"It's upsetting to see that he will miss this chance to show his class at an international level, especially on the back of picking up two end-of-season club awards. However, I am sure he will be back in the frame in the future.
"In light of Beno's injury, we are looking for appropriate cover ahead of starting the 2018-19 campaign."