Coach Byron Scott is working to manage Bryant's minutes, notably on the second night of a back-to-back, in which the Lakers play three games in four nights.
Johnson was injured on Sunday, in the Lakers' 88-87 win over the Indiana Pacers (13-22), 88-87.
The 29-year-old All-Star has great range extending all the way to the three-point line. He can score in the mid-range and at the basket.
The Lakers will counter with Ed Davis, who has been a bright spot for the Lakers this season, averaging 8.2 points and 7.1 rebounds on 63.2% shooting.
Davis is a solid, mobile defender with a knack for blocking shots (1.2) a night.
The Lakers will likely try a number of defenders on Aldridge, including Jordan Hill, Carlos Boozer, Robert Sacre, Tarik Black and Kelly. Black has yet to make his debut with the team, after the Lakers picked him up off waivers in late December.
Damian Lillard is one of the top point guards in the league, averaging 21.7 points and 6.4 assists a game.
Lillard can be difficult to guard off the dribble. He can also pull up and shoot from mid-range as well as make three-point shots at a 38.9% clip.
Wesley Matthews is one of the NBA's most prolific three-point shooters at 40.1%, averaging 16.9 points a game.
Young's scoring without Bryant becomes more important, but the Lakers need a defender to step up in the absence of Johnson. If not Young, or Kelly playing out of position, perhaps Ellington gets time at small forward, despite standing at 6-foot-4.
Portland is one of the top teams in the Western Conference. The Lakers would be hard-pressed to get a win at full strength, let alone without two starters.