The defender was forced out of the FA Cup goalless draw at Sheffield Wednesday last weekend when his knee "locked" just before kick-off, but has recovered in time to feature this weekend.
He came in for high praise from manager Carlos Carvalhal too, who said: "He is progressing a lot in many different areas, they are not all on the pitch. He is a better and better player and is progressing. One of the best central defenders in the Premier League, Im absolutely sure."
Although both sides are facing a relegation battle, they are currently on unbeaten runs with Swansea not losing in their last 10 matches in all competitions, while Brighton are unbeaten in their last five, including a 3-1 win against Coventry in the FA Cup last weekend.
But manager Chris Hughton says the Premier League remains his biggest focus, saying: "For me, its quite obvious [the priority], its about making sure this club is a Premier League club next season.
"Thats the only way in the initial years [after promotion] you give yourself and the club a chance to develop at the highest level over these years.
"The FA Cup is a wonderful trophy and were absolutely delighted to be in it, but the biggest priority for us is the Premier League."
Swansea boss Carlos Carvalhal believes Alfie Mawson is one of the best defenders in the Premier League and is continuing to progress a lot
Elsewhere for Swansea, Lukasz Fabianski and Federico Fernandez will also return after being rested at Hillsborough, but Leon Britton (pelvis) and Renato Sanches (hamstring) remain out.
Brighton have no fresh selection concerns. Tim Krul has recovered from the whiplash suffered against Coventry, while record signing Jurgen Locadia could make his league debut after scoring against the Sky Blues.
Jiri Skalak and Steve Sidwell (both ankle) remain the only players unavailable.
