Call it the splash heard all the way from Cleveland.

Terry Rozier, selected with the 16th pick by the Celtics on Thursday night, was poolside at a club in Cleveland with his family when the news arrived. Clad in a suit and accompanied by his younger brother and nephews, the 6-foot-1 Louisville guard jumped in.

“I had to jump in,” said Rozier. “The celebration was great.”

Though he called the prospect of being taken that high a “tossup,” many considered the Celtics’ selection of Rozier at 16 a surprise. There were, for example, a number of dumbfounded season-ticket holders at the team’s draft party at the Seaport Hotel.

Danny Ainge had said earlier in the week that he was “trying” to fall in love with someone, and that clearly must have been the case for the Celtics’ president with Rozier. The team worked the guard out twice and also interviewed him at the draft combine in Chicago.

Though the roster already is filled with undersized scoring guards like Isaiah Thomas and Avery Bradley, Rozier had certain intangibles that Celtics management couldn’t resist.

“(Rozier) is the fastest guard in the draft. Gets to the rim. Worked him out twice. Voracious defender,” a member of management texted shortly after the pick was announced.

Brad Stevens drove that concept home further when weighing Rozier’s intangibles, like energy and defensive potential, against the elements in his game that need improvement, like his inconsistent jump shot.

“He’s a player,” Stevens said when asked about Rozier’s apparent lack of a true backcourt position. “I answered this about Marcus a lot. Is Marcus Smart a point guard, is Marcus Smart a 2-guard? It doesn’t matter to me. He’s a basketball player who wins. That’s a huge thing. The one thing that was consistent when talking to people around him is that kid studies and works as much as anyone, and that’s a huge quality.”

Stevens and Ainge admit that the now-overcrowded backcourt will have to be sorted out over the summer.

“Obviously we have a lot of guards and will figure it out,” said Ainge. “We will have some tough choices to make.”

Stevens, who predicts that the Celtics will send an especially small, quick team into summer league season, looks forward to the process.

“The first question I asked doing my first draft is, do you draft based on need or best person available, and the consensus is best person available,” Stevens said of the process that led to Rozier. “There will come a point when you hope they can complement each other in a position-less way, but there’s going to be a lot of competition. We have a lot of young players.”

And Rozier is sure to come in with the sense he has something to prove. He doesn’t sound worried.

“I faced the same thing when I went to Louisville – there were a lot of guards,” he said. “But I’m not the kind of person who worries about who’s there. I worry about how I can get on the floor.”

Last winter that meant playing out of position, at shooting guard, once teammate Chris Jones left the team.

Rozier shot 33.1 percent over two seasons at Louisville from 3-point range. Asked to score last season, his 3-point percentage dropped from 37.1 percent as a freshman to 30.6 percent with the increased shooting load. He shot 40.1 percent overall and was a combined 12 for 38 in his last two NCAA tournament games against North Carolina State and Michigan State.

But Stevens isn’t too concerned about those numbers.

“The biggest thing is he has that burst the really good point guards have,” said Stevens. “He can really defend right now. He’s a guy in pick-and-roll who can be really good. It will be a lot of fun to watch him and Marcus next week. We may be playing super small ball in summer league, but it will be a lot of fun.”