Boston Celtics coach Brad Stevens speaks about the NBA basketball team’s draft picks Thursday, June 20, 2019, during a news conference in Boston. The Celtics selected Romeo Langford with the 14th pick as they look to fortify a roster facing massive uncertainly with free agency looming. (AP Photo/Elise Amendola)

BOSTON — The Boston Celtics continued to amass more young talent via the NBA draft as they look to fortify a roster facing uncertainly with free agency looming.

The Celtics began Thursday night holding the 14th, 20th, 22nd and 51st picks.

After taking former Indiana guard Romeo Langford at No. 14, Boston selected former Washington guard Mattise Thybulle with the 20th pick, whose rights it planned to send to Philadelphia.

Boston used its 22nd pick to take former Tennessee All-American and two-time Southeastern Conference player of the year Grant Williams. The Celtics selected LSU guard Tremont Waters in the second round with the 51st pick.

“I was just really filled with joy,” Langford said of his selection. “Waiting there a lot of emotions going through my head, going through my body. When my name was called by Boston, I was super-excited.”

In his lone season at Indiana, the 6-foot-6 Langford played through a thumb injury and led the Big Ten and finished sixth nationally in freshman scoring, averaging 16.5 points.

Langford had surgery on his thumb this spring and said he was just recently cleared to begin shooting again. He is the third wing player Boston has selected in the first round in the last four drafts.

Langford said he hasn’t had a chance to watch many NBA games recently because he didn’t have cable in college.

But Celtics coach Brad Stevens called him “a guy that we think has a lot of things that can translate to the NBA.”

Stevens said Williams, who averaged 18.8 points and 7.5 rebounds as a junior, plays with a point guard’s mind.

“You can run offense through him,” Stevens said. “He thinks the game. He’s a tough, tough guy, and he’s a versatile player who can shoot the ball.”

Williams said he’s ready to fill whatever hole the Celtics need him to.

“I’m a guy that can guard multiple positions,” he said. “I’m a guy who on the offensive end can initiate offense and also be a guy screening, moving the ball efficiently and knocking down open shots. So I feel like fit very well.”

It was an intriguing night for Boston as it trudges into the start of free agency on June 30 knowing that pursing All-Star center Anthony Davis is no longer a possibility after the Pelicans agreed to trade him to the Lakers. The Celtics also could potentially lose two All-Stars this summer with Kyrie Irving and Al Horford having elected to out of their player options for next season.

The Celtics have been one of the most talked about teams in the NBA for the past two years since acquiring Irving and Gordon Hayward

But after injuries to both disrupted their first season together in 2017-18, locker room infighting and inconsistency on the floor resulted in a woefully disappointing finish this past season.

The preseason favorite in the Eastern Conference, the Celtics finished the regular season 49-33. They were eliminated 4-1 in the conference semifinals by the Milwaukee Bucks.

Boston still has a solid core of talented young players, led by Marcus Smart, Jayson Tatum and Jaylen Brown. But they could lose another young asset this summer in Irving’s backup Terry Rozier, who is a restricted free agent.

Despite the potential roster shake-up, president of basketball operations Danny Ainge said there is a lot of optimism about what’s next.

“I’m excited about our team going forward. I like where we’re headed,” Ainge said. “I like the core, young group of guys. And I think it’s gonna be really fun. … I don’t know exactly what the teams is gonna look like when it’s all done. But free agency starts in 10 days or so and we’ll have more answers then.”

Coach Brad Stevens is also hopeful about the future.

“We’ll have some uncertainty as we move forward, but we’re in pretty good shape,” he said. “We feel good about our foundation and want to learn from certainly the disappointment we all shared but we’re optimistic about the future. That’s been the vibe in the whole building.”