Steve Smith remains the Panthers’ most dangerous offensive weapon, but the team is hoping to solidify its number-two receiver spot.  Keary Colbert, Drew Carter and rookie Dwayne Jarrett are candidates to fill the slot.  Jarrett, a second-round pick from USC, appears to have the best chance to win the job long-term.   Carter has great speed and has shown flashes in his three years with the Panthers but has never been a consistent offensive threat.  Colbert had a solid rookie season in 2004 but struggled with injuries the following year and was unproductive in 2006.  Colbert, Carter and Jarrett will have another opportunity to state their case Friday night when the Panthers continue preseason play against New England.