Mendenhall expected to play Cardinals' opener

The Arizona Cardinals expect running back Rashard Mendenhall to play in their season opener Sept. 8 at the St. Louis Cardinals, according to CBSSports.com.

The team is also looking to trade running back Ryan Williams.

Mendenhall injured his right knee in the Cardinals' 24-7 preseason loss to the San Diego Chargers on Saturday. An MRI taken Sunday reportedly revealed a mild sprain. He will likely wear a brace over the knee for the time being. He has also had tendinitis throughout training camp.

Williams, a second round draft choice in 2011, has struggled with injuries. He played in five games last year and rushed for 164 yards.