The All-Star forward injured his left hand in Portland's win on Monday over the Sacramento Kings. Head coach Terry Stotts told oregonlive.com that Aldridge had an MRI, but tests were inconclusive, so another is scheduled for this week.
"For whatever reason, they needed to do another one," Stotts said.
The team missed their best player on Wednesday in a 118-113 road loss to the Phoenix Suns.
The Blazers couldn't overcome a monster night from the Suns three-man point guard wrecking ball. Eric Bledsoe had a career-high 33 points, 10 rebounds and six assists; Isaiah Thomas finished with 27 off the bench and Goran Dragic added 16.
Nicolas Batum paced Portland with 27 points -- 10 of those coming in the fourth -- and Damian Lillard and Wesley Matthews scored 22 apiece in the setback.
"We did a great job fighting back and giving ourselves a chance down the stretch," Lillard said. "They made some big plays at the end of the game and they did what they needed to do to pull it out."
The Blazers trailed by 25 in the second quarter and fought back. A 15-point lead vanished in the frame, and Batum's 3-pointer at 4:05 gave Portland its first lead since the opening quarter.
Batum hit a deep 3-ball two minutes later to increase Portland's lead to five before Dragic hit a corner 3 and Bledsoe converted a three-point play to put Phoenix back in front.
Thomas Robinson and Markieff Morris then traded runners and Bledsoe made four free throws in the final 10.9 seconds to secure the win.
The Blazers host Washington on Saturday before heading east for four games to end the month.
The Celtics have dropped three straight, including the opener of this six-game western odyssey. Boston fell to the Los Angeles Clippers, 102-93, on Monday.
Boston fell for the fifth time in its last six games despite getting 59 points from its bench. Brandon Bass paced the Celtics with 17 points and Marcus Thornton chipped in 15 while shooting 3-of-6 from 3-point range. Marcus Smart scored 14 with four triples and seven assists, and Evan Turner contributed 10 points and 10 rebounds.
The Celtics trailed by 23 in the third quarter, but responded. Thornton's 3 with 3:50 to go made it a one-possession game, but Los Angeles tightened up its defense the rest of the way. The Clippers scored eight of the next nine points, and the Celtics shot just 1-of-5 from the field after the Thornton triple. Chris Paul's 3 with 48 seconds left punctuated the win.
"We can't be down by that much," said Celtics coach Brad Stevens. "We took a lot of contested shots in the first half, and that's not good. We were better in the second half. We closed it to three, but we missed a couple of good looks down the stretch."
The Blazers bested the Celtics on Nov. 23 in Boston and have taken four straight in this series. The two teams have split the previous six meetings in Portland.