Roughly half the teams in the NBA has a head coach hired within the last two years, so with heavy annual turnaround, there are several college coaches who could move up to the next level in 2015.

In 2014, nine teams hired a new head coach and four had no prior experience. In 2013, nine teams hired a new coach. However, only eight teams have made new hires from 2010-2012, leaving four coaches who have been employed with their current team before then.

Gregg Popovich, the San Antonio Spurs, is the only active coach in the NBA who was not hired in the 2000s and has been employed 12 years longer than the next-longest-tenured coach.

Such a turnover makes it hard to predict which teams will be looking for a new coach, but there is an especially promising crop in the college game. Here are the top five NBA coaching targets in college, as of now.

1. Billy Donovan

NBA teams are rumored to be pursuing Donovan on an annual basis and he even accepted the Orlando Magic coaching job in 2007 before returning the offer. If the Magic have another bad year and Donovan indicated his availability, there is a fit, especially since the Gators' coach was apparently thrilled with Orlando's draft class.

2. Fred Hoiberg

ESPN's college basketball expert Dick Vitale is high on the Iowa Cyclones next season and their success is tied to Hoiberg. NBA teams pay top dollar for coaches who have a high basketball IQ, can motivate a group of players and can effectively communicate. According to Vitale, that describes Hoiberg to a tee.

3. John Calipari

Yes, coach Cal got a nice raise and contract extension from the University of Kentucky, but the offer the Cleveland Cavaliers made to him is mind-boggling. He turned down a 10-year contract worth $80 million. Kentucky is competitive every year, despite heavy freshman turnaround, so those offers are likely to keep coming to Calipari.

4. Tom Izzo

Izzo only promised to stay at Michigan State one more season, though his statements during the offseason sounded like he had not future plans to leave. Izzo was also reportedly sought after by the Cavs as well and, though he has been at Michigan State since 1995, he did not rule out a jump to the NBA.

5. Kevin Ollie

When UConn gave Ollie his extension and raise, the coach did imply that he wanted to stay their long-term. However, Ollie's stock skyrocketed after leading the Huskies to the National Championship, so another strong season could boost it even more.