Wide receiver Anquan Boldin briefly tested his sore hamstring on Thursday, then watched the rest of practice.

If Boldin can’t play in the opener against San Francisco on Sunday, the Cardinals may look to Jerheme Urban for help.

“If for some reason they have to lean on me more in the game, I’m ready for that,” Urban said after sweating out a practice on a 100-degree day.

Coach Ken Whisenhunt said he remains hopeful that Boldin will play when the defending NFC champions open the regular season in University of Phoenix Stadium, which was not sold out as of late Thursday afternoon.

“He came out early and did some limited work with us, and then we shut it down just so we wouldn’t stress it,” Whisenhunt said. “I really don’t know where he is at this point. Hopefully, he’ll continue to improve and we’ll have a shot for the game on Sunday.”