Today's top sports stories:

The best pound-for-pound boxer in the world, Floyd Mayweather Jr., will put his undefeated record on the line six times over the next three years. The Forbes-anointed world's richest athlete left HBO for Showtime, and his first fight will be May 4 against Robert Guerrero. [ESPN]

Oscar Pistorius, the South African Olympic runner who is accused of murdering his girlfriend, says that he didn't mean to kill her, but instead thought he was shooting an intruder. [NYDN]

Thursday's NBA trade deadline is fast approaching, so which teams need to make a deal. Sports Illustrated took a look at Eastern Conference contenders and tried to deduce what would make the most sense for them. [S.I.]

At this Sunday's Daytona 500, Danica Patrick will be in the pole position, thanks to her 196-plus-mph qualifying lap—but racing with all the other drivers out there on the track with you is a whole other story. Plus, all the other whispers about Patrick's rise to stardom will only amplify if she once again can't pull out a major victory. [Washington Post]

And in Peruvian-soccer news, goalie Juan Flores of Club Union Comercio collapsed from heat exhaustion during the game, and an opposing player named Piero Alva decided that would be a good time to score on him. We think that was a bit unsportsmanlike of Alva. [Deadspin]