We’re still a few weeks away from the October 2 preseason opener vs. Charlotte, but there’s one Celtic who’s been in the middle of high caliber competition already. Rookie PF/C Daniel Theis was a standout for the German national team at 2017 FIBA EuroBasket, the most prestigious non-Olympic international tournament in basketball. The 25-year-old combo big posted averages of 10.9 PPG and 6.3 RPG at a blistering 56% FG clip over 23.8 MPG, per FIBA.basketball.

The Germans had an impressive run with notable victories over Italy and France, before eventually losing to a buzzsaw Spanish team that is perennially favored to win EuroBasket. Against Spain, Theis held up well against NBA stars Pau and Marc Gasol, and promising New York Knicks sophomore, Willy Hernangomez, all three of whom tower over the 6’9 Theis.

His best game came against a talented French team that featured a front court littered with NBA veterans in Joffrey Lauvergne, Boris Diaw, and Kevin Seraphin. Theis exploded for 25 points and 6 boards, frequently exploiting the French big men with confident spot up jumpers and a deft scoring touch around the rim. He also showed relentless effort on the glass, frequently keeping possessions alive by out hustling longer and bigger opponents.

Watching Theis at EuroBasket, it’s clear that he’s comfortable being utilized in a multitude of ways. Overall, Theis displays a great feel for the game. He sets good screens and tactfully interchanges between rim runs and pick and pop jumpers based on what the defense presents. He’s a capable floor spacer, shooting 41% on 3 pointers last season with Brose Bamberg of the German League (per basketball-reference), albeit on only 1.4 distance attempts per game over his European career. It’s safe to question whether Theis can sustain his shooting prowess when he inevitably sees an uptick in attempts in the trey happy NBA, particularly in Boston’s spacey offensive system. But his shot looks good overall. He has a decisive and smooth motion, with a textbook high release and backspin, sporting no wasted movement in his form. He possesses all the tools to develop into a dependable stretch 4 or 5, a role that the Celtics will try to replace after Kelly Olynyk signed in Miami.

Theis doesn’t put the ball on the deck very often, if at all. At most, you’ll see him pump fake and take one power dribble before going into his shot or pass. He’s more comfortable being utilized as a stationary shooter or roaming around the basket to clean up garbage. With ball handlers like Marcus Smart, Jayson Tatum, Terry Rozier, Abdel Nader, and Shane Larkin running with the second unit, Theis’ lack of dribbling skills won’t be an immediate concern.

That said, passing, playmaking, court vision, and rim protection remain open questions for Theis’ continued development. He had an underwhelming 0.698 assist to turnover ratio in five European professional season per basketball-reference and he’ll have to adapt to making quicker decisions in Boston’s fast-paced and pass heavy offense. Brad Stevens emphasizes creating imbalances by shifting opposing defenses from side to side with constant ball movement. It translated into Celtics big men being relied upon to make speedy and effective passes. Olynyk, Al Horford, and Amir Johnson all had assist percentages in the double digits last season, with Horford leading all NBA big men with 5.0 dimes per game. Theis’ passing doesn’t need to dazzle like Horford’s, but he needs to consistently make the correct reads if he wants to survive in Stevens’ system.

Theis averaged 1.5 blocks per 36 minutes last season, which was equivalent production to that of Dwight Howard and Draymond Green. But NBA athleticism is in a completely different stratosphere than what Theis is accustomed to, and while he possesses favorable leaping ability, he won’t immediately instill any fear for opposing players driving to the cup. Theis doesn’t project to be a prolific rim protector, but he’ll raise his shot-altering abilities if he can learn to contest with verticality and perfect his weak side rotational timing. His growth as a basket protector is something to keep an eye on.

Around the rim, Theis shows impressive catching and finishing skills in traffic. He makes veteran-like anticipatory positioning shifts to help enlarge passing lanes for driving teammates. At Eurobasket, it led to him earning dish offs and wrap around passes from Atlanta Hawks guard Dennis Schröder, resulting in a slew of easy layups and dunks. Theis is an early candidate for Tommy Heinsohn to anoint him as the next “great pair of hands” with Tyler Zeller now in Brooklyn.

You can expect a lot of rim runs with Theis. Brose Bamberg loved putting him in side pick-and-roll, which cleared space for him to make hard rim runs straight down the lane. Theis finishes lob passes at an impressive rate and can play well above the rim. While he seems to prefer jumping off of two feet, he is equally impactful exploding off of only one. Check out this nuclear tomahawk dunk he had in the Round of 16 win over France.

Theis is an undersized center at 6’9, but his mobility is his most NBA-ready trait. In the below clip, an above the arc 1-5 screen forces him onto Sergio Rodriguez, a veteran point guard who is six inches shorter and fifty pounds lighter. Theis does a good job sliding defensively along perimeter to stay in front of Rodriguez in isolation. After Rodriguez gives the ball up, Isaiah Hartenstein (number 55) inexplicably leaves Pau Gasol open for a 3-pointer. Recognizing Gasol’s range, Theis quickly reacts and rotates to close out and contest as the shot clock winds down.

Plays like this are becoming more frequent in the NBA. It’s easy to use screens to force big men into unnatural switches on smaller and quicker players. Guards are becoming adept at exploiting big men who can’t reliably defend the perimeter in isolation (see:Kevin Love versus the Warriors).

Take two things away from the above clip: Theis’ switchability and his lightning quick execution in defensive rotation. It shows that he can make up for his lack of size with fluid and rangy athleticism and schematic intellect, and that combination should translate well for him in the league. You won’t find many rookie big men can offer the physical capability to hang with quick guards and the mental capacity to read and react to cover up for a teammate’s defensive breakdown. Danny Ainge and Brad Stevens have been publicly preaching positional versatility all summer, and gameplay like this will help Theis find a role on this team. Like all rookies, the NBA game will initially move at lightyear speed, and most neophytes are over consumed with their individual primary responsibilities, rather than approaching gameplay from a team oriented systemic mentality. If Theis can consistently replicate the veteran maturity that he displayed in this clip, he’ll earn a big role in Stevens’ rotation.

“It’s a perfect situation for me, especially with Brad Stevens as a coach and how the team developed over the last couple of years, from when they got better every year.” Theis said in a telephone conference with the Boston media in July. “You can tell just from watching the games it was great team chemistry and everybody was fighting for each other.”

The Celtics recent success has been constructed on an identity that they play with incessant effort and toughness on a nightly basis. While it’s still too far early to make any formal conclusions on Theis, he should fit right into the mentality. He played with incredible energy and resilience in his EuroBasket games and that should serve him well with the Celtics coaching staff and TD Garden fanbase. Here he is sprinting past all five Spanish players for an easy bucket when Germany was down 11 points with under a minute to play.

With Ante Zizic shipped to Cleveland before he could even unpack his suitcases in Boston, the big man depth is now noticeably thin. Behind Horford (who continues to insist that he’s a power forward) and Aron Baynes (career 14.1 MPG), there is no obvious answer for who should eat up the leftover minutes at the 5 spot. The Celtics are flirting with Andrew Bogut for their final roster spot, but for now, Theis seems like a logical choice given his five seasons of professional experience in Europe. His teams won the previous three German League championships, which suggests that he’s prepared for big pressure stints if Boston makes a deep run in the postseason. Like any rookie, his minutes largely hinge on how quickly he can adjust to the pace and skill of the NBA, but his performance against like-talent at EuroBasket provides some evidence that he will answer the bell.