The veteran guard had hoped to practice Monday and be cleared to return from nerve root irritation in his back that has kept him out for all but six games this season, but suffered a minor, unrelated tweak in his back before practice and was not able to participate.
The Lakers say the future Hall of Famer will try to practice again Thursday with the hopes of playing in Friday's game against the Charlotte Bobcats.
Nash, 39, had spent the past two weeks working with his personal trainer in Vancouver while the Lakers were away on a seven-game road trip. A Lakers spokesman said Nash's work "went well" and he was "on board to have a practice before he comes back and plays, but there was just sort of a freakish thing."
The new "tweak" is not believed to be serious, or related to the previous injury, the spokesman said.
"He's fighting some big odds, as we all know as we get older," Lakers coach Mike D'Antoni said of Nash, who will turn 40 on Feb. 7. "But if anybody can do it, he can."
The news was more encouraging on some of Nash's backcourt teammates. Point guards Jordan Farmar (hamstring) and Steve Blake (elbow) were cleared Monday morning to resume basketball-related activities and could return next week, if there are no setbacks.
The Lakers said both have been ruled out of this week's games, but they were able to ramp up their activity in Monday's light practice.
"It was great, man. I've been bored," said Farmar, who has been out since Jan. 1 with a tear in his left hamstring. "With this injury, you don't feel too injured. It doesn't hurt. You just have to be patient and wait your turn. It's hard, especially seeing them struggle and not being able to contribute.
"You're not in the huddles or on the court to say things. I try to just pull guys aside, tell them things, try to keep their spirits high. But you definitely can't be as involved."
The Lakers went 2-5 on their seven-game, 12-day road trip to fall to 16-29 on the season. They are just 3-16 since Dec. 21.
"It's tough in this business. You start building habits. When things go bad as a team, they become habits too and you start doing things that just aren't winning basketball," Farmar said. "We play well enough to win games, but we just don't do the little things."
Just knowing that reinforcements are on the way should help matters, or at least their spirits.
Kobe Bryant is scheduled to be re-evaluated on Tuesday to see if the fracture in his lateral tibial plateau has healed. Xavier Henry is out at least another week after an MRI showed no change in the bone bruise in his knee. But Blake, Farmar and Nash all seem to be nearing returns in the next week or so.
"We're not going to look at it like, 'Is it too late or not?' We're going to play the next game like it's the last game and then just see where we are a month from now," D'Antoni said. "It'll be really good to get some of these guys back and you can start winning something.
"We're in a tough situation. We're in a ditch and we have to crawl out of it. But the more guys you have, the easier it is to crawl out of it.
"The guys coming back are going to add some enthusiasm. They're looking forward to playing again. The guys that are here will be glad to get the help. So yeah, the atmosphere will change. We just have to make sure that it's a winning atmosphere and I'm sure we will."