BOSTON

Jared Sullinger had back problems. Fab Melo’s troubles came in the classroom. The Boston Celtics hope the two big men they drafted on Thursday night will help fix some of their issues on the court.

At their best, Sullinger was a productive scorer from the inside and the perimeter for Ohio State and Melo was an outstanding defender who blocked 10 shots in one game last season for Syracuse.

The Celtics took another Orange player, swingman Kris Joseph, with the 21st choice in the second round, the 51st overall.

With free agent Kevin Garnett contemplating retirement, the two first-round picks may have to be quick studies and make a speedy transition to the NBA.

“We’ll get both of them next week,” Boston coach Doc Rivers said. “We’re going to two summer leagues because we anticipated that we’re going to have a lot of work with our young guys.”

Last year’s draft picks, forward JaJuan Johnson and guard E’Twuan Moore, played sparingly as rookies from Purdue.

Sullinger, taken with the 21st pick, and Melo, chosen 22nd, are better known nationally than those players. They met in the Elite Eight on the Celtics home court this year with Ohio State winning 77-70 — behind 19 points and seven rebounds from Sullinger — before falling to Kansas 64-62 in the NCAA semifinals. Both are solid rebounders.

Boston obtained the 22nd pick in the trade that sent center Kendrick Perkins to Oklahoma City in 2010-11. Rivers said the Celtics were interested in trading the two picks for a higher one but “for any of the guys we had interest in we couldn’t even come close.”

Sullinger and Melo join a team that made it to the seventh game of the Eastern Conference finals, further than widely expected, before losing to the Miami Heat.

The 6-foot-9, 280-pound Sullinger was projected as a lottery pick before the season, averaged 17.5 points and 9.2 rebounds as a sophomore and was a two-time consensus All- American. But his draft stock had fallen, in part because of concerns about disk problems, which Ainge said could still cause trouble but were not severe enough for the Celtics to pass on him.

Only two Ohio State players, Jerry Lucas and Michael Redd, scored more points in their first two college seasons than Sullinger’s 1,282.

The 7-foot, 255-pound Melo led Syracuse with 5.8 rebounds and 2.9 blocks per game while averaging 7.8 points last season but missed the NCAA tournament because of academic issues. He had played sparingly as a freshman but was named Big East defensive player of the year as a sophomore.

“We have to teach him the Celtics way,” Rivers said. “We have to teach him how to work and understanding playing as a winner. There’s a lot of work that has to be done, but I love starting with size and potential. He has both of those things and if he has great character then we have a chance.

“For us to get a 7-footer at that pick is a good pick for us.”