Distraught Blues skipper Terry was due to undergo an MRI scan today after leaving Stamford Bridge on crutches and with a brace on his right knee following yesterday's 1-1 Premier League draw with Liverpool.
Terry was left writhing in distress 10 minutes before half-time after Luis Suarez fell on his leg following an accidental collision between the pair.
Following almost five minutes' of treatment, he was carried off on a stretcher with his head in his hands and was attended to by club medics before being allowed home.
But Di Matteo said: "At centre-back we have cover."
Yesterday's match was Terry's first domestic appearance since his four-match racism ban.
He could face much, much longer than that on the sidelines if the injury to the same knee he had surgery on in February turns out to be serious.
Di Matteo said: "When a player reacts like that, it's a concern. We hope it's not a serious injury, but we'll see."
Terry was consoled by his manager before disappearing down the tunnel.
"I was concerned about his well-being," Di Matteo added.
"We just got him back into the team after the ban.
"It was great seeing him out there."
Indeed, the defender had been enjoying a dream return to action when he powered the European champions ahead from a corner after 20 minutes.
Di Matteo said: "He started the game very well, showing the qualities he has, and the experience and influence.
"It's a real shame he had to come off as he was having a very good game."
Chelsea badly missed Terry during his ban and they struggled defensively after he went off, allowing Suarez to snatch a draw.
Di Matteo bristled at suggestions a third league match without a win was evidence Chelsea were suffering another bout of the winter blues.
They ended the weekend three points behind Manchester United in third place, two weeks after being four points clear.
Goalkeeper Petr Cech said: "We have what it takes to win trophies and challenge the best teams in Europe and the Premier League but you have to win your games.
"We are still getting experience and I believe we will improve every game.
"We've hit a difficult two or three games where we didn't win and this isn't what we wanted but you can see we are progressing as a team."