Blake is out indefinitely after an ultrasound Thursday confirmed a moderate strain of his right hamstring.
Blake left Wednesday's Game 2 loss to the Spurs with 4:51 remaining in the fourth quarter and had to be helped off the court by teammates after the game. He hurt his hamstring while driving to his right and trying to beat his man off the dribble when he felt a "sharp pain."
The 10-year veteran had been averaging 14 points, 4 rebounds, 2.5 assists, 2 steals and 1.5 blocks in the playoffs while shooting 41.7 percent from 3-point range, but just 39.3 percent overall.
The Lakers, down 2-0 in the first-round playoff series, list Nash as doubtful for Friday's game after he received two epidural injections in his back and a cortisone shot in his right hip Thursday.
"I'm not too bad," said Nash, who tweaked his right hamstring pushing the ball up the court just before halftime Wednesday. "Obviously I wish I felt a lot better, but I got the procedure done [Thursday] morning and fingers crossed it will help.
"I have been called a doctor of chemistry by some people in the media, but I couldn't make a prediction."
Nash, who missed the Lakers' final eight regular-season games because of nerve damage in his right hamstring stemming from a right hip injury before coming back to average 12.5 points and 4.5 assists in the postseason, said there is "absolutely" a chance he does not play Friday.
"I'm very concerned," Nash said. "It's really frustrating. Very, very frustrating. Especially because I was at the point where I was actually excited with the way I felt to start the last two games even though I still couldn't sprint completely and I was not moving as well as I'd like, I felt like I could still be effective and find a way to help the team and impact the game."
Photos surfaced on Instagram of the 39-year-old guard in a wheelchair after receiving his third and fourth epidural injections in a little more than a week, but Nash was able to leave the Lakers' practice facility walking on his own without a noticeable limp.
Jodie Meeks, who suffered a sprained left ankle in the Lakers' Game 1 loss Sunday, did not play in Wednesday's 102-91 loss and was scheduled to have an MRI on Thursday. He is doubtful for Game 3.
"I think Steve [Nash] has a better chance than Meeks [for Game 3]," D'Antoni said.
Now the spotlight is on Morris, who averaged 5 points and zero assists while playing 15.5 minutes through the first two games of the series.
The Lakers also could look to Chris Duhon -- who started nine games during the regular season when Nash and Blake were injured but has yet to appear in the playoffs -- or Andrew Goudelock. Goudelock, who will be honored at Staples Center on Friday for being named the D-League MVP, was called up from the Rio Grande Valley Vipers shortly after Kobe Bryant tore his Achilles. Goudelock played six minutes of garbage time Wednesday, registering 2 points, 1 steal and 1 assist, finishing the game after the Lakers trailed 91-74.
The depleted backcourt will put even more pressure on Dwight Howard and Pau Gasol to perform down low. Through the first two games, Howard is averaging 18 points, 12 rebounds and 3 blocks on 62.5 percent shooting, but his production has been curtailed by his 4.5 turnovers per game. Gasol is averaging 14.5 points, 12.5 rebounds and 5 assists -- all increases from his regular-season numbers of 13.7, 8.6 and 4.1 -- but he's shooting just 40 percent from the field.
"You don't try to put everything on them, but they know that they have to dominate," D'Antoni said. "They're going to try to give you more. Now, they're playing well. So, I don't want anybody to think they got to give you more because they're not giving you enough. They're giving us a lot, but it would be great if they could dominate everybody."
Howard did not let the injury news affect his outlook for the team.
"We have total confidence that we can come back and win this series," Howard said. "We believe in each other, we've worked too hard to get into the playoffs. We had to fight to get in and we're not just going to give up because we're down and we have a lot of guys that are injured."