Swansea defender Neil Taylor will miss the rest of the season with a broken ankle.
The 23-year-old full-back suffered the injury in the 20th minute of Saturday`s draw with Sunderland, and was immediately taken to hospital. The Wales international has since had surgery and it has been confirmed that he has broken and dislocated his ankle in three places.
"The surgeons worked hard on Neil's injury and did a very good job," said Swansea's head physio Kate Rees on the club's official website. "He is comfortable and the surgeons are happy with the operation. While he should make a full recovery, the extent of the injury means Neil is likely to miss the rest of the season."
Roberts, who joined the Swans from Wrexham last summer, had appeared in all three of the club's Premier League games this season, having enjoyed a successful debut season in the top flight.
After Taylor's injury, City twice had to come from behind to earn a point - a result that ended their winning start to the season - against the Black Cats. For manager Michael Laudrup, though, the guts and determination shown by his players suggests a positive season is ahead.
"We have played four games, if you include the Capital One Cup, but this was the most important match for me as manager," he said.
"I saw so many great things, so much character in the team."
Laudrup also hailed the performance of 19-year-old Ben Davies, who replaced Taylor at left-back and is now in line for a run in the team.
Midfielder Ki Sung-yueng made his Premier League debut as a substitute, and Laudrup believes that shows the strength of his squad.
"If we look at Ben, he is a young guy and he did a great job in a really difficult moment, and when we were down to 10 men Ki came in and kept the ball for us with Jonathan (De Guzman) and Leon (Britton) and I thought that was really good," concluded Laudrup.