Derrick Rose injured his right knee Friday night and the Chicago Bulls star, who sat out last season following surgery on his other knee, did not return during a 98-95 loss to the streaking Portland Trail Blazers.
Wesley Matthews had a season-high 28 points and Damian Lillard added 20 to help the Trail Blazers run their winning streak to nine games.
Rose led the Bulls with 20 points, five rebounds and three assists but was assisted to the locker room with 3:20 remaining in the third quarter. The 2011 NBA MVP tore the anterior cruciate ligament in his left knee during the 2012 playoffs and missed last season while recovering from surgery.
The top pick in the 2008 draft and a three-time All-Star, Rose was averaging 15.4 points this season.
Carlos Boozer had 16 points and Luol Deng added 15 points and 14 rebounds for Chicago.
Nicolas Batum scored 17 points for Portland, on its longest winning streak since the 2007-08 season. Robin Lopez had 13 points and 16 rebounds. LaMarcus Aldridge added 13 points on 4-of-20 shooting.
The game was tied at 88 before Kirk Hinrich made two baskets to give the Bulls a 95-91 lead with 3 minutes left. But then Batum knocked down a 3-pointer, Matthews hit a jumper and Aldridge made two free throws to pull it out for the Blazers.
The Bulls led by 20 in the second quarter but were outscored 34-9 in the third as Portland stormed back and took the lead.
Portland was coming off a 4-0 road trip that included a 97-87 win over Milwaukee on Wednesday, but the Blazers looked as though they were going to get blown out in the first half. Chicago jumped out to an early lead and was up 51-31 late in the second quarter before taking a 59-44 advantage into the break. Aldridge was barely a factor, missing nine of his 10 field goal attempts in the first half.
Portland came out strong in the third, erasing the deficit and taking the lead when Mo Williams hit a 3-pointer. The Blazers entered the final quarter with a 78-71 advantage. Portland shot 51 percent in the quarter while Chicago was 4 for 12.
The Bulls had won five straight before losing to Denver 97-87 on Thursday night in the opener of a six-game road trip.
NOTES: Bulls G-F Jimmy Butler sat out a second game with turf toe and will miss the entire road trip. Butler and Matthews were teammates at Marquette. ... Portland has won 10 of the last 12 matchups with Chicago at home. ... Aldridge was drafted No. 2 overall by the Bulls in 2006 but got traded on draft day to Portland for Victor Khryapa and the draft rights to Tyrus Thomas.