Chelsea captain Reece James is potentially facing weeks out after suffering another hamstring injury.
The right-back has sustained his 10th hamstring injury since December 2020, just days after signing a new six-year contract with the club.
James, 26, has played six of the last seven Chelsea matches and stayed largely injury-free this season, missing just five games due to fitness issues.
"I had to come through a lot, two or three years of struggles and setbacks," he said last week after signing his new deal. "I'm in a really good place at the moment. My body is feeling good, I'm playing on a regular basis, two or three games a week."
His latest injury comes at a crucial time for Rosenior's side, who have slipped to sixth in the Premier League after winning just one of their last five games as they look to overturn a 5-2 deficit against PSG on Tuesday night.
"Reece felt something in his hamstring against Newcastle," head coach Liam Rosenior said on Monday. "Really frustrating and disappointing one for us.
"We don't know the full extent of the injury, but it rules him out of tomorrow's game.
"With a hamstring injury, it's never great, and for Reece, we can get him scanned and then we know more. We know what an important player he is and leader in the group - he's our captain.
"Any player at any time, if you feel something, you're going to be worried about it. Once we get the full diagnosis then we can make a statement about it."
Asked if James was facing weeks out, Rosenior added: "Could be."
James looked set to be named in Thomas Tuchel's England squad for the World Cup, which must be selected by May 30, but he will now miss friendlies in March against Uruguay and Japan.
Meanwhile, Estevao took part in Chelsea training on Monday after missing the last six matches with a hamstring injury, while Levi Colwill was also present as he continues his return to fitness following ACL surgery.
Goalkeeper Filip Jorgensen didn't take part due to a groin issue and neither did right-back Malo Gusto, who is ill.
"With Malo [Gusto], he's ill today so we'll have a look at him for tomorrow," Rosenior added in his press conference.
"Estevao is back in training. He's back part of the group, we'll assess whether he can take part in the game in some way tomorrow.
"Filip [Jorgensen] felt something in his groin after the PSG game and again, we're getting him scanned to find out the full extent of that injury."
Pedro Neto has escaped punishment for pushing a ball boy during the first leg against PSG after being charged by UEFA, who have issued a warning.
"He's a top player, he apologised for the incident in Paris," Rosenior said. "There was no bad intent, he just wanted to get on with the game and UEFA have made the right decision."
Tuesday March 17: Paris Saint-Germain (h) - Champions League last 16 second leg, kick-off 8pm
Saturday March 21: Everton (a) - Premier League, kick-off 5.30pm, live on Your Site
Saturday April 4: Port Vale (h) - FA Cup quarter-final, kick-off 5.15pm
Sunday April 12: Man City (h) - Premier League, kick-off 4.30pm, live on Your Site
Saturday April 18: Man Utd (h) - Premier League, kick-off 8pm
Saturday April 26 - Brighton (h) - Premier League, kick-off 4.30pm
