Trip to Chelsea comes too soon for injured Swansea duo Ki Sung-Yueng and Jefferson Montero

Ki Sung-Yueng and Jefferson Montero remain sidelined for Swansea City's tricky upcoming visit to Premier League leaders Chelsea, manager Paul Clement has confirmed. The resurgent relegation battlers travel to Stamford Bridge in high spirits having risen from the foot of the table to 15th after winning four of six top-flight matches since Carlo Ancelotti's former right-hand man arrived to succeed Bob Bradley.

Midfielder Ki has not featured for Swansea since replacing Leroy Fer during the second half of a 2-1 victory over Southampton on deadline day, missing back-to-back matches against Manchester City and Leicester City. The South Korean international sought specialist opinion on a knee injury and Clement appeared hopeful before last week's 2-0 defeat of the champions that, after taking more advice, he would be available again within three to four weeks.

Montero, meanwhile, has yet to play for the new manager after sustaining a hamstring tear during Bradley's final game in charge – a miserable 4-1 drubbing by West Ham United on Boxing Day.

The Ecuadorian winger is not expected to return to the training pitch until March. Captain Leon Britton is fit again after back spasms, but Nathan Dyer has been ruled out for the rest of the season after undergoing surgery on a ruptured achilles.

"Ki is still unavailable as is Montero," Clement was quoted as saying by Wales Online at his pre-match press conference. "Dyer [is] out long term, he was back today for the first time and everyone else [is] available."

Clement, who previously spent five years at Chelsea as an academy coach before returning in 2007 and later won the double at Stamford Bridge alongside Ancelotti, also provided an update on contract negotiations with defender Federico Fernandez. The former Argentina centre-back recently revealed that he would probably sign a new deal within the next week, although it appears that a final agreement has yet to be reached.

"It's still not quite there but things are moving in a very positive direction. Hopefully [it will happen] soon. I can't say exactly when but the talks are positive and I don't see any reason why it won't happen."

Addressing the future of Borja Baston, who has scored just one goal since completing a club-record £15m ($18.8m) switch from Atletico Madrid in August 2016, Clement refused to be drawn on speculation that the underwhelming striker would return to Spain this summer.

"No. After the window closed, those are the players that are going to be here until the end of the season. [There have been] no discussions about any players and the summer at this point. [We are] only focusing on getting the right results.

"Of course [Borja has a role to play in the run-in]. The squad's not that big. We've got 20 fit outfield players, that's not a massive amount. A couple more injuries and the squad's coming down even further. Everyone's training, everyone's pushing hard and they need to be ready."