Call him an international man of mystery.

Vitor Faverani arrives in Boston as a great unknown, but on a young Celtics team thin on size at center, there exists an opportunity for the 25-year-old big man to prove himself early on the NBA stage. Vitor Faverani has shown considerable offensive skills, but his defense could be an issue. Rodolfo Molina/Getty Images

Here's what we know about Faverani: The Brazilian native landed in Spain as a teenager and began his professional career at age 17. The 6-foot-11, 260-pound power forward/center has been slowed at times by injuries, which didn't aid his cause while being passed over after declaring for the 2009 NBA draft. He spent the past two seasons with Valencia BC of Spain's Liga ACB and averaged 9.3 points and 4.6 rebounds over 17 minutes per game in 23 appearances this past season.

Celtics president of basketball operations Danny Ainge said the team has kept close tabs on Faverani in recent seasons. According to overseas reports, Faverani worked out privately for Boston last month as part of a 10-day showcase for NBA teams, and the Celtics came away impressed enough to pay a reasonable escape clause (one overseas report pegged it at 500,000 euros, which would be $661,650).

Reports also have indicated that Faverani signed a three-year, $6 million contract, meaning the Celtics used a portion of their midlevel exception to sign him (likely with an option for the final season). For a team now dancing on the luxury tax apron and hard-capped after receiving Keith Bogans in a sign-and-trade with the Nets, that's no small commitment despite being a reasonable contract.

The lingering question: What can he do on the floor?

The scouting report from those who have watched Faverani overseas is nearly universal: a skilled and athletic offensive player but a question mark on the defensive end.

That's confirmed by the advanced stats from his play overseas. In 34 games for Valencia last season, Faverani averaged 0.976 points per play (324 points over 332 plays), which ranked him in the 72nd percentile among all international players, according to Synergy Sports data. His post numbers won't wow you (0.888 ppp), but he thrived last season in the pick-and-roll (1.2 ppp) and off of offensive rebounds (1.361 ppp). He's prone to turnovers, but his offensive skills are obvious.

He isn't afraid to fire away from the perimeter either, having showcased 3-point range in recent seasons, but he made just 5 of 28 shots (17.9 percent) from beyond 17 feet last year. He does have nice touch around the basket, shooting 66 percent in non-post-up situations around the hoop.

Teams quickly will identify that he thrives around the right blocks and likes to run the middle of the floor in transition and off the pick-and-roll. He'll have to prove he can finish as effectively against NBA back lines that will be bigger and more physical than what he's seen overseas.

The bigger question mark is whether Faverani can elevate his defensive play in the NBA. According to Synergy data, he allowed 0.88 points per play, ranking in the 42nd percentile among all international players last season. He was exploited at times in the post (1.081 ppp, 10th percentile), but was stout against the pick-and-roll (0.632 ppp, 79th percentile).

Film study from Valencia clips last season reveal a player who, defensively, seems to be slow to react around the basket at times and sometimes gets caught on his heels. The Boston Globe offered two interesting takes on Faverani from NBA scouts, and one revealed an entertaining nickname: "El Hombre Indestructible." For a player who has battled injuries and needs to show more defensive toughness, that's a nickname he's going to have to reestablish stateside. But his desire to joust will serve him well at this level.

Ainge has noted he's content with Boston's center depth at the moment, though Faverani joins Shavlik Randolph (whose contract is non-guaranteed) and the still raw Fab Melo (a Brazilian countrymate) as the only players on the current roster who would be dubbed pure centers. (Second-round pick Colton Iverson remains unsigned as Boston juggles its roster.)

It's more likely that Boston will mix and match up front with its growing stable of versatile 4s, maybe utilizing Jared Sullinger as a back-to-the-basket 5, while rookie Kelly Olynyk plays a more typical power forward role at times. Boston also has Kris Humphries and Brandon Bass at a log-jammed power forward spot that could get a facelift before training camp depending on how Boston trims salary and manages its roster space.

But Faverani undeniably is an intriguing addition. It might be unfair to expect too much in his first season in the NBA, but he's still young enough to mold. He's another young body with potential whom Boston will allow new coach Brad Stevens to work with. At a low-risk salary, it's worth a roll of the dice on a high-mystery big man.