CAMDEN, N.J. -- Shawn Long thought he was coming to the Sixers training complex on Monday morning for a workout.

Imagine his surprise when the big man found out he was being called up from the Delaware 87ers and signing a 10-day contract.

"It still hasn't settled in yet,” Long said after going through shootaround.

The Sixers used an NBA injury exception to sign Long for their depleted frontcourt. They have four injured players (Ben Simmons, Joel Embiid, Jerryd Bayless, Tiago Splitter) who are out for at least the following two weeks.

"Right now [I am] a five, a stretch five,” Long said. "I'm still working on my shot, trying to be more consistent on the pro level. Rebounding the ball hard, that's something I really want to focus in on … playing hard and bringing that toughness to the game."

Long went through summer league and training camp with the Sixers. He joined their Development League affiliate after being waived.

Long was averaging 20.2 points, 11.1 rebounds and 1.3 blocks in 29.5 minutes per game for the 87ers. He was selected to the D-League All-Star game.

Long said he has learned about "respecting the grind" of the season and is ready to jump into an NBA setting.

"I think I've adjusted to the physicality of the pro game," he said. "That's something that was tough for me at first."

There is a good chance Long sees playing time Monday night against the Bucks. Jahlil Okafor is doubtful because of right knee soreness. That leaves Richaun Holmes as the only true center, and he is listed as probable (right hamstring tightness).

"It's a big opportunity for me and I'm looking to capitalize on it," Long said.

Okafor participated in parts of shootaround on Monday. He received treatment on Sunday, which included work in the pool and activation exercises. Gerald Henderson (left hip soreness) also is probable after going through partial shootaround.