Johnson was signed to an Exhibit 10 deal by the Thunder on Friday, Clemente Almanza of USA Today reports.
Whitehead signed an Exhibit 10 contract with the Thunder on Friday, Clemente Almanza of USA Today reports.
Jefferson (back) has yet to fully participate in team activities and remains without a timetable for his return, Erik Slater of ClutchPoints.com reports.
The Thunder maintain that Mara is cleared to play in the NBA despite a contract dispute with his former Spanish club, Basket Zaragoza, Marc Stein of The Stein Line reports.
Brown will remain on a minutes restriction for Wednesday's regular-season opener against Charlotte, Brian Lewis of the New York Post reports.
Mitchell finished with seven points (3-10 FG, 0-4 3Pt, 1-2 FT), three rebounds, one assist and one steal across 24 minutes in Thursday's 116-89 preseason loss to Houston.
McCain recorded eight points (3-13 FG, 0-8 3Pt, 2-2 FT), six rebounds and two steals over 21 minutes in Thursday's 116-89 preseason loss to the Rockets.
Barnhizer recorded nine points (4-5 FG, 0-1 3Pt, 1-2 FT), a rebound and two assists across 12 minutes in Thursday's 116-89 preseason loss to the Rockets.
Gilgeous-Alexander recorded 17 points (5-12 FG, 2-5 3Pt, 5-5 FT), a rebound, three assists and a block across 26 minutes in Thursday's 116-89 preseason loss to the Rockets.