"Two games is what I'm thinking about right now, but I don't see him missing the playoffs," Jackson said of the time he expects Blake to miss. "I don't know. It supposedly affects adults more than it does kids."
Jackson said the team would survey its players to find out who has and who has not had chicken pox in the past. Kobe Bryant, Ron Artest and Andrew Bynum are among the players who have not had the contagious illness before, although Bynum said he did receive the vaccination for it.
Blake did not practice on Monday because of a fever. His illness was not identified as chicken pox until after shootaround Tuesday. The back-up point guard is averaging four points and 2.2 assists in 20 minutes per game this season. Blake scored nine points and made all three of his 3-point attempts in his last game Sunday against Oklahoma City.
As for Barnes, the forward missed 26 games while recovering from surgery to repair a light tear of the meniscus in his right knee in January. He was limited in practice Monday and struggled through shootaround Tuesday.
"I tried to straighten my knee out and I felt a sharp pain in the back of my knee," said Barnes, who averages 6.7 points and 4.3 rebounds in 19.2 minutes per game on the season.
Barnes had some bright moments during the Lakers' five-game losing streak, including a line of 10 points and six rebounds against the Golden State Warriors.
"This is something that kind of jumped out at us," Jackson said. "We didn't expect it to happen like that."
With Blake out indefinitely, the Lakers called up guard Trey Johnson from the D-League's Bakersfield Jam and intend to sign him Wednesday for the remainder of the season. He will travel with the team to Sacramento on Tuesday night.
Johnson, who was one of the Lakers' final two cuts in training camp, averaged 25.5 points, 4.5 assists and 4.2 rebounds this season for the Jam and also averaged 4.0 points and 1.6 assists in seven games earlier in the season as a call-up with the Toronto Raptors.
Dave McMenamin covers the Lakers for ESPNLosAngeles.com.