The midfielder received treatment for eight minutes in the 2-0 defeat at Stamford Bridge after a heavy collision with Chelsea captain Gary Cahill.
Mason required surgery at St Mary's Hospital, where he was visited by Cahill and Chelsea club captain John Terry, while Hull skipper Michael Dawson also checked in on the 25-year-old on Monday.
Hull confirmed Mason was conscious and speaking during Dawson's visit and on Tuesday the club provided an update with further positive news.
"The club can confirm that Ryan Mason continues to make excellent progress after sustaining a skull fracture in Sunday's game against Chelsea," a statement read.
"He will continue to be closely monitored by staff at St Mary's Hospital over the next few days, whilst also remaining in contact with our medical team to assess his progress.
"There will be no further updates from the club until there are any changes in Ryan's condition. We also ask that people respect Ryan & his family's privacy whilst he remains in hospital."