All NCAA underclassmen who want to test their NBA draft status have until April 10, 2015 to declare and subsequently withdraw from the Draft. If a player declares after the 10th, he cannot rescind the decision. All players who wish to be drafted must file paperwork with the NBA by April 29, 2015. As with many of these deadlines, all of this favors the college coaches and NBA. As for Olivier Hanlan, I think BC fans can read a few things into it.
It doesn't appear that Hanlan is going to "test the waters." BC's season ended weeks ago. If he wanted to find out what NBA teams thought of him, he would have entered his name by now, so that he still had the freedom "take his name out" this week. I expect the April 10 deadline to pass without issue.
The April 11-29 window still remains an opportunity for Hanlan, Christian and BC fans. If Olivier wants to go regardless of what scouts think, he still has three more weeks. I have no inside information, but the lack of rumors and scouting reports still listing him as a late second rounder lead me to believe Hanlan is coming back. At this point, it makes the most sense for him. Hanlan will be an old draftee if he waits one more year, but he can keep improving his game and reputation. He also has a decent shot at ACC Player of the Year. That one award wouldn't assure him of being drafted, but it would maximize his profile.
Regardless of his final year in college, Hanlan's professional path seems destined for overseas basketball. Let's hope the upside of a final college season and the outside chance of the NBA keeps him around the Heights one more year.