Rutherford said the Penguins likely would have a better idea regarding how much time Murray will miss in 10-14 days.
"It's not an unusual injury, I think," Rutherford said. "That's probably the best way to say it. It's not necessarily common, but it's something that should heal 100 percent. And I think the biggest thing for us, and it's what I said to the doctor, we don't need to push this too quick."
Penguins coach Mike Sullivan called Murray's injury unfortunate and expressed confidence in Fleury.
"I've said all along that we're pretty fortunate to have two quality goaltenders like we have, two guys who are NHL ready and have accomplished as much as those two guys have accomplished at that level," he said. "Fortunately it's not going to keep [Murray] out for an extended period of time. In the meantime we have Marc, who obviously has been so good for this team for so long."
Fleury was not available for comment Saturday.
Murray was in goal when the Penguins won the Stanley Cup last season. The 22-year-old rookie went 15-6 with a 2.08 goals-against average and .923 save percentage in 21 Stanley Cup Playoff games. That came after he went 9-2-1 with a 2.00 GAA and .930 save percentage in 13 regular-season games.
He became the starter when Fleury sustained a concussion during a game against the Nashville Predators on March 31. Prior to his injury, Fleury went 35-17-6 with a 2.29 GAA, .921 save percentage and five shutouts in 58 games. He returned to play two games during the Stanley Cup Playoffs.
Fleury, the Penguins' goalie for the past decade, likely will be in goal when they open the regular season against the Washington Capitals at Consol Energy Center in Pittsburgh on Oct. 13.
If Murray misses three weeks, he could return in time for the second game, Oct. 15 against the Anaheim Ducks. A six-week absence would see him miss 12 games, but he could return Nov. 5 for a Stanley Cup Final rematch against the San Jose Sharks at SAP Center.
Whenever Murray returns, he is expected to battle Fleury, the Penguins' career leader with 357 wins, for the starting job. Sullivan said he doesn't feel the decision will be extraordinarily difficult because their performance will dictate playing time.
"I'm a firm believer that I think the game always sorts those types of situations out," Sullivan said. "We're in a business that's competitive by nature, so there's always going to be that internal competition. At least you're hoping there's going to be that internal competition, because that's what makes, I think, everybody be at their best.
"And so we're fortunate that we have the depth that we have at the goaltender position. As far as how we manage the position moving forward, certainly with us, the coaching staff, we've discussed potential scenarios. … To a certain extent, the players themselves have a lot of influence on the types of decisions that coaches make."
Behind Fleury on the depth chart are Tristan Jarry and Leland Irving, who is in training camp on a professional tryout contract. One of them could start the season as the backup, or Rutherford could try to make a trade for a goaltender.
Jarry, 21, went 17-13-3 with a 2.69 GAA and .905 save percentage in 33 games with Wilkes-Barre/Scranton last season.
Irving, 28, was 12-22-6 with a 2.68 GAA and .913 save percentage in 41 games last season with Iowa, the Minnesota Wild's AHL affiliate. He has 13 games of NHL experience, with the Calgary Flames in 2011-12 and 2012-13.
Rutherford said the Penguins don't feel the need to rush back Murray.
"We're early in the season," Rutherford said. "We have good goaltending and let's make sure it's 100 percent."