Philadelphia 76ers star Ben Simmons will undergo MRI for his injured lower back on Sunday. According to Adrian Wojnarowski of ESPN, the Sixers are reportedly concerned about the extent of Simmons' injury.

There is some level of concern surrounding the possible nature of the injury, league sources tell ESPN. A clearer picture is expected after testing on Sunday in Philadelphia.

The Sixers will surely learn more about the former first overall pick's injury when he gets further testing on Sunday. Until the results come out, Philadelphia can only wait and hope that the results come in clean.

Simmons exited early in the first quarter of Philadelphia's 119-98 loss to the Milwaukee Bucks on Saturday. After getting fouled on a layup by Bucks center Brook Lopez, Simmons appeared to re-aggravate the injury. He left the game shortly and did not return.

The Aussie-born guard already sat out Philly's previous contest against the Brooklyn Nets on Thursday due to lower back tightness. He obviously tried to give it a go in a supposedly blockbuster game against Milwaukee, but it seems like doing so only made matters worse.

Philadelphia certainly wishes that there isn't any major damage on the former Rookie of the Year's back. Though there have been concerns with his fit alongside fellow franchise star Joel Embiid, the Sixers will undoubtedly still need Simmons if they want to have a deep playoff run this season.

Simmons is Philadelphia's primary ball handler and their offense essentially runs through him. Moreover, he is also arguably their best perimeter defender. Losing a an elite two-way star like him for a long period of time could be catastrophic for a team that is still looking to salvage its season.