Michael Crabtree struggles to describe the style of the San Francisco 49ers' offense.

"I wish I could describe it to you, but that would be hard," said Crabtree.

The 49ers added Randy Moss and Mario Manningham to their wide receiver depth chart this offseason.

"The sky's the limit," Crabtree said. "We got everything we need. It just depends on us going out on Sunday and putting it together, making plays, making things happen. That's when it counts. We're looking good at practice. Been practicing real hard, running real hard. We just need to carry it over to Sunday."

The 49ers gave few glimpses during the preseason of how they plan to use the offense.