Just how good can Jared Sullinger be for the Boston Celtics?

When last year’s Celtics fell to the New York Knicks in the first round of the NBA playoffs, it concluded a season full of disappointment, especially given the team’s lofty expectations coming into the preseason. Some of the squad’s more hyped offseason acquisitions in Jason Terry and Courtney Lee proved inconsistent at best. Meanwhile the Celtics got off to a sluggish start that, barring two winning streaks in January and February, they could never quite snap out of.

There is little doubt that Rajon Rondo’s torn ACL in late January dampened any hopes of an extended playoff run, but Jared Sullinger’s injury just five days after Rondo’s was a costly one as well. That’s because Sullinger was showing real signs of improvement during his rookie season just prior to his injury. In fact, if you can forgive me for picking some arbitrary endpoints here, you can see a noticeable uptick in Sullinger’s production after Christmas last season when compared to his play prior to December 25:

After a bumpy first two months in green, Sullinger saw increases in nearly every major category during his last month of the season, and considering his surge in minutes over this period, it’s pretty clear Doc Rivers noticed the progress in Sullinger’s game as well. The 6’9" big man recorded three double-doubles and averaged 11.5 points and 11.1 rebounds per 36 minutes after Christmas, giving the Celtics some valuable minutes off the bench.

Even more encouraging, though, has been Sullinger’s performance this preseason after returning from back surgery. Brad Stevens has shown little hesitation in putting Sullinger in the starting lineup through the team’s first six games, and even though the power forward is supposedly not 100% conditioning-wise, he has been one of the team’s major bright spots throughout a bumpy preseason slate. His stats—11.2 points and 5.2 rebounds in 20.9 minutes per night—don’t jump out at you immediately, though his per-36 minutes averages of 19.5 points and 9.0 rebounds are impressive. More than anything, Sullinger’s instincts, confidence, and ability around the basket have been evident, with the 21-year-old picking up right where he left off last January.

Of course, Sullinger’s role on this team will be far different than it was a year ago. Barring any surprises, the 21-year-old will be expected to start and play major minutes for the Celtics this season.

So just what can we expect from Jared Sullinger moving forward?

First off, it’s worth mentioning that Sullinger isn’t your typical 21st overall pick. Concerns over his durability and size limited his draft stock, even though his production at Ohio St. resembled that of an early lottery selection. Indeed, those injury fears proved prescient last season, and his lack of height for the power forward position will always limit his ultimate upside.

But during his brief time in the NBA, Sullinger has shown a knack for creating space and getting his shots off amongst the tall trees in the paint. His 49.3% field-goal percentage and 53.4% true shooting percentage in 2012-13 were strong numbers for a rookie and someone so undersized, even if most of his shots came from the post.

Compare Sullinger’s numbers during his first NBA campaign with those of another small big man and former Celtic in Glen Davis, and Sullinger’s future prognosis looks even more favorable. Not once in six seasons has Davis been able to match Sullinger’s 49.3% field goal percentage, while Sullinger also holds an edge in rebounding, with his 17.5% total rebounding percentage representing a much higher mark than Davis has ever been able to put up during his NBA career.

For the moment, Sullinger is an essential part of the team’s present and, given his ability at the age of 21, looks likely to be a valuable piece well into the future. He is a strong rebounder for a power forward, regardless of his small stature, and has already shown the capability to score against taller defenders.

Although Sullinger may never be the dominant player some thought he would become at Ohio St., he looks likely to reward the Celtics immensely for taking a chance on him in the 2012 draft. No matter what he ultimately becomes, Sullinger will play an integral role in the team’s growth and development over the next few seasons.