Around 1pm Crabtree tweeted the words "Bay Area..." suggesting he is in Oakland today.
Bay Area...— Michael Crabtree (@KingCrab15) April 6, 2015
As Rapoport points out, Crabtree had previously visited the Dolphins who reportedly offered him $3 million per seasonwhich Crabtree rejected as he is looking for at least $4.5 million per season. The Dolphins completely purged their receiving corps this off-season and are in need of competent replacements. They also don't have a lot of money to spend in free agency -- a problem the Raiders don't have with some $22 million still to spend under the cap.
Crabtree going unsigned this long and leaving Miami without a contract suggests his $4.5 million asking price is more than most teams are willing to pay. This is not altogether surprising considering he has been overvaluing himself since he was drafted when he held out to get paid more than his draft position at 10 overall.
In his six NFL seasons, he has surpassed 1000 yards once (1105 in 2012). He didn't have a single 100-yard game last season.