In Oakland in 2012, Hagan started two games and caught 20 passes for 259 yards in 14 total games. Since getting picked in the third round by Miami in 2006, Hagan has been something of a journeyman playing for the Giants and Bills as well.
Hagan would be considered a depth player for the Jets and at best would be a spot starter much as he has been over the course of his career.
I have to think the news that the Jets worked out Hagan doesn't mean that they would now bring him in, in addition to their signing of Obomanu. To me, signing of Obomanu and the working out of Hagan indicates that that the Jets were serious about upgrading the receiver spot before camp because of the team's struggles to keep receivers on the field.