BOSTON — The Boston Celtics made a surprise pick in the first round of the NBA draft Thursday night, taking guard Terry Rozier of Louisville with the 16th pick.

At 6-feet-1 and 190 pounds, Rozier lacks bulk like several of Boston’s other guards, including 6-3 Avery Bradley and 5-9 Isaiah Thomas. Rozier averaged 17.1 points per game as a sophomore last season but hit only 41 percent of his shots.

With so many guards on the roster, “we may be playing like super small ball in summer league, but it will be fun to see,” Celtics Coach Brad Stevens said.

He said so many guards will help the top ones develop their own games rather than measure themselves against each other.

“The best people don’t compare, they compete,” Stevens said.

Rozier moved to point guard late in the season after Chris Jones was dismissed from the team. Rozier helped the Cardinals to the Elite Eight, where they lost in overtime to Michigan State.

He said he’s not troubled by competing with so many guards.

“I had kind of the same thing when I went to Louisville, a lot of guards,” he said. “I’m not pretty much worried about who’s there. I’m pretty much worried about how can I get on the floor.”

But first he had an unusual celebration after being drafted.

“I got to jump in the pool with my clothes on,” Rozier said. “I had a lot of fun tonight, an unbelievable feeling. It was great.”

The Celtics had been expected to go for a frontcourt player and 6-foot-11 Bobby Portis of Arkansas was available. He’s a good outside shooter but wouldn’t provide the defensive presence inside that the Celtics lack.

The Celtics again ignored the inside game with their second pick of the first round, taking R.J. Hunter, a 6-6 shooting guard from Georgia State.

In the second round, with the 33rd pick, Boston chose power forward Jordan Mickey of Louisiana State, who led the nation in blocked shots despite being an undersized 6-7.

With their final pick, the 45th overall, Boston went for yet another point guard, selecting 6-1 Marcus Thornton of William & Mary.

Hunter is known for his 3-point basket with 2.7 seconds left that gave 14th-seeded Georgia State a 57-56 victory against third-seeded Baylor in this year’s NCAA Tournament.

His coach and father, Ron Hunter, fell from his stool during the play while coaching with an Achilles tendon injury.

R.J. Hunter averaged 19.7 points as a junior last season and hit 39.5 percent of his 3-point attempts. For his college career, he averaged 18.4 points.

Mickey led the nation with 3.64 blocks per game last season while averaging 15.4 points and 9.9 rebounds.

Interior defense was a major problem for the Celtics last season when they finished with a 40-42 record but were swept by the Cleveland Cavaliers in the first round of the playoffs.

Mickey, who spent two seasons at LSU, was the second player in school history, following Shaquille O’Neal, to block at least 100 shots in a season.

He blocked 106 as a freshman and 113 as a sophomore last season.

The Celtics have stockpiled draft picks. From 2015-18 they have a potential 21 choices, 10 of them in the first round.

Danny Ainge, the Boston president of basketball operations, had plenty of draft choices to include in a trade to move up in Thursday’s draft.

But few of Boston’s current players seemed attractive as part of a package.