The Boston Celtics are rumored to be pursuing Philadelphia 76ers center Nerlens Noel to try to boost their current frontcourt options after the injury to Al Horford.

Horford, who was signed by the Celtics to a four-year $113 million contract in July via free-agency, was currently sidelined by the NBA's concussion protocol after he was accidentally hit in the head by a teammate during practice.

Like Us on Facebook

The nine-year veteran has missed Boston's last four games because of the protocol, including their 118-93 loss to the Washington Wizards at the Verizon Center on Wednesday night.

CBS Local Boston reported that there is "no progress" with regard to Horford's health status, which could make him miss more games.

Celtics head coach Brad Stevens is reportedly concerned about his frontcourt's depth at the moment as he continues to start Tyler Zeller at the center spot. Aside from Horford, small forward Jae Crowder is also out with a sprained ankle.

Boston is on a three-game losing streak without their two starters, and point guard Isaiah Thomas has expressed concern about the remaining players' lack of passion.

"These signs aren't good. We're not giving our all on the defensive end," Thomas said. "We can have five starters out (but) you can definitely, it's a mindset thing on that end, and we've got to do a better job on that."

Bleacher Report noted that the Celtics could "consider a move" for Noel after he and the Sixers recently failed to reach a contract extension agreement.

Without an extension, Noel is set to become a restricted free agent at the end of the season, and Philly is at risk of losing him for nothing in the process. Trading Noel before that happens would at least give them some value moving forward.

Noel has also expressed his frustration about sharing the roster with Jahlil Okafor and Joel Embiid, who finally made his NBA debut this year. The former Kentucky standout told reporters during the Sixers' preseason Media Day that it is "silly" to have "three starting centers" in one squad and he expects the Sixers to fix the issue before February's trade deadline.

TagsNBA Trade Rumors, NBA Trade Rumors 2016, Nerlens Noel, philadelphia 76ers, Boston Celtics, al horford