The 76ers’ problems at the center position are beginning to multiply.

Joel Embiid has missed the last six games after tearing a ligament in his left ring finger.

Now, Al Horford, Embiid’s replacement, is listed as questionable with a left-hand sprain for Monday’s 3 p.m. matinee in Brooklyn against the Nets

In addition, two-way center Norvel Pelle has only one day left toward the maximum number of days the Sixers are allowed to have him on the roster on his two-way deal. The plan was to sign him to the 15-man roster or release him after his 45 days.

At the moment, the Sixers say they will list Pelle as available for Monday’s game, but according to a team official, the status could be changed.

Horford hurt his left hand while being fouled by the Knicks’ Reggie Bullock and falling hard on it with 6 minutes, 31 seconds left in the third quarter of Saturday’s 90-87 win atNew York.

Horford stayed in the game before leaving with 2:41 left in the quarter. He would return and with 8:12 left in the fourth quarter, but after the game Horford said his (opposite) left hand was sore.

“It was definitely uncomfortable,” he said Saturday night. “I have played ... in this game you always play through injuries. I just want to make sure I did what I could….”

Before Embiid’s injury, Horford was starting at power forward and moved to center when Embiid would leave the game.

During the past six games in Embiid’s absence, Horford has averaged 13.5 points, 7.0 rebounds and 5.3 assists in 33.1 minutes. He has shot just 25.7% from three-point range over those six games.

For the season, Horford is averaging 12.5 points, 6.6 rebounds and 1.0 blocked shots and is shooting 32.4% from beyond the arc in 31 minutes per game.

The Sixers (28-16) are 4-2 without Embiid during his recent absence. They are 7-6 in the 13 games Embiid has missed this season.

The Sixers’ other center is veteran Kyle O’Quinn, but he has not seen much action recently. Before playing 15 minutes and 40 seconds in Friday’s 100-89 win over the visiting Chicago Bulls, O’Quinn had not appeared in six consecutive games and 11 of the previous 12. He did not play Saturday against the Knicks. O’Quinn was effective against the Bulls, with six points (3 of 5 shooting), five rebounds and two blocked shots.

The Sixers could also go with a small lineup and use 6-foot-8 Mike Scott at center. Another alternative, although not likely for extended minutes, is have point guard Ben Simmons play some center. The 6-10 Simmons played center for part of the game in the Sixers’ 109-98 home win over the Boston Celtics on Jan. 9, the first game that Embiid missed with his finger injury.

The Sixers have won three in a row and Saturday’s victory snapped a six-game road losing streak. They are 20-2 at home but just 8-14 on the road.

Brooklyn (18-23) has lost three in a row and 10 of 12. The Nets are also dealing with an injury at center. In the Sixers’ 117-106 win over the visiting Nets on Wednesday, backup center DeAndre Jordan suffered a dislocated middle finger. Jordan is listed as out against the Sixers. Former Sixers forward Wilson Chandler is also out with left hamstring tightness.