During training camp and this summer's exhibition season, second-year Seahawks wide receiver Jermaine Kearse showed his explosiveness.The former University of Washington standout caught six passes for 72 yards and two touchdowns to earn a roster spot, and nailed down duty as the team's No. 1 kick returner by returning one for 107 yards and a score against the Denver Broncos.As Seattle quarterback Russell Wilson said in August, "Jermaine deserves the most improved award. He was great before he came in, but he's electrifying out there. He does a lot of great things."So when the 49ers travel to Seattle Sunday for a nationally televised evening matchup against the Seahawks at CenturyLink Field, Kearse will be on the mind of San Francisco's kickoff coverage team.If the Niners can contain Kearse – who didn't get a chance to return a single kickoff in a victory over the Carolina Panthers this past Sunday – they can keep the Seahawks bottled up deep on their side of the field. That was something San Francisco didn't do last December when it was beaten at CenturyLink by the 'Hawks 42-13 and Seattle kick returner Leon Washington averaged 31 yards on his two returns, including a...