The Celtics appeared to be in trouble when it was reported that Al Horford and Kyrie Irving were both headed out of town. Signing Kemba Walker changes everything.
The first big move of the summer was the Boston Celtics agreeing to terms on a four-year, $141 million max contract with former Charlotte Hornets point guard, Kemba Walker. The All-Star will be the third different starting point guard for Boston in the last five seasons.
Boston initially started the Brad Stevens era by handing the reigns over to Isaiah Thomas. Thomas began his career with the Sacramento Kings where he grew into an effective scorer who saw steady increases in playing time with each passing season. The next stop was Phoenix where Thomas took a backseat to Goran Dragic and Eric Bledsoe in the Suns’ ill-fated attempt at housing three NBA rotation-worthy point guards on one team.
Once with the Celtics, Thomas was unleashed. The freedom, spacing, and movement principles that define Stevens’ offense allowed Thomas to flourish with Boston in ways we only caught glimpses of at his previous two stops. Paired with an assortment of high-quality supporting teammates, Boston was once again among the Eastern Conference’s best teams and by the 2017 NBA Playoffs, the team was in the Eastern Conference Finals against a Cleveland Cavaliers “superteam” comprised of LeBron James, Kyrie Irving, and Kevin Love.
However, after being swept Danny Ainge felt that the Celtics as constructed had reached their peak. Ainge sought to upgrade from Thomas to a higher-end point guard who could operate in a similar fashion to Thomas but produce greater team success. Boston would trade Thomas and other assets to the Cavaliers in return for Irving and other pieces.
In the first season, it seemed as if Ainge’s thinking was correct as the Celtics were still one of the top teams in the East and they had improved their record by two wins. Irving would miss the postseason after being sidelined late in the season due to complications following knee surgery in March of 2018 to alleviate pain from a 2015 surgery after he suffered a patellar fracture in the 2015 NBA Finals.
This past year, things did not go as planned. From Irving announcing his intentions to re-sign with the franchise, to his “ask me July 1st” press conference at Madison Square Garden, to the team flaming out in five games against the Milwaukee Bucks in the second round, things did not meet expectations in Boston — especially after watching Al Horford, Jayson Tatum, Jaylen Brown, and Terry Rozier lead them to Game 7 of the Eastern Conference Final the previous season.
For all of his talents, Irving is someone with an eccentric personality. While he was clearly a better player than Thomas, Thomas’ underdog approach created a vibe and cohesion among the Celtics. Whereas Irving had trouble finding the right balance as the team’s leader.
With rumors swirling for months that Irving had his eyes set to play elsewhere, Ainge and the Celtics had to move quickly to find a replacement as Rozier also expressed his wish to leave the team in free agency this summer. The team quickly moved to secure a commitment from Walker after the Hornets declined to give Walker a four-year ($190 million) or five-year ($221 million) max contract that he sought.
Given the data and results of the past four years in Boston, this moves signifies that Ainge is willing to admit that the move from Thomas to Irving was a mistake — or an overcorrection if you want to use a less negative word. In Walker, the team is getting a player who not only mirrors the game and skill set they had with Thomas but another fringe all-star talent who personifies the “chip on the shoulder” attitude that defines Boston’s sports teams.
Using Synergy, here’s a breakdown of the percentages that Walker and Thomas (in 2016-17 with the Celtics) used their five most used play types: Pick-and-Roll Ball Handler (Thomas: 34.4 percent vs. Walker: 46.8 percent), Transition (Thomas: 15.8 percent vs. Walker: 15.9 percent), Spot-Up (Thomas 13.8 percent vs. Walker 9.4 percent), Isolation (Thomas 9.1 percent vs. Walker 8.2 percent), and Hand Off (Thomas 11.1 percent vs Walker 7.8 percent).
Irving is one of the best one-on-one players in the league — his isolation numbers in his two seasons with Boston according to Synergy were 13.2 percent and 13.8 percent in 2018-19 and 2017-18 respectively. Thomas and Walker meanwhile can attack in isolation but they do a lot more damage out of pick-and-rolls. Why is that? Both are phenomenal pull-up 3-point shooters.
Give either the slightest bit of room as they come off a ball screen and you might as well add three points to the scoreboard right when the shot attempt goes up. Thomas made a living off these, especially in 2016-17 where SecondSpectrum tracked him as taking 25.5 percent of his 3-point field goals as pull-up jumpers (he shot 35.7 percent). In Charlotte, Second Specturm tracked Walker at 29.3 percent of his 3-point field goals were pull-up jumpers (he shot 35.6 percent). With Horford likely signing somewhere else this summer, Boston is going to rely more on Walker to act as a scorer in pick-and-rolls. Expect for a barrage of pull-up 3-pointers.
And it’s likely that opposing defenses will, there are two ways that defenders can combat that. The first is switching and having the defender who is guarding the screener switch onto Walker and Walker’s defender take the screener — a likely option given the names that fill out Boston’s interior depth. Second, the defense could opt to double team Walker off the screen and force another player to beat them in a four-on-three scenario.
Let’s first tackle switching. Thomas saw these at times with Boston, and Walker has seen his fair share with Charlotte. Both players understand that the more separation that they can create at the beginning the better chance of success they have in the end. As noted above, defenders have to respect the pull-up 3-pointers but Walker and Thomas are explosive enough off the dribble that one false step from the defense is enough to open a path directly to the rim.
Irving’s ball handling abilities are legendary in basketball but he often had a propensity to play with his food when attacking a mismatch — he also liked to settle for mid-range shots instead of going all the way to the rim far too often. With Walker and Thomas, both know that their lack of size limits them from what they can do when they are in the paint. Once they find a lane to the rim they take it and both have become great finishers at the rim over their careers.
Double teaming off ball screens has become a go-to tactic for teams playing against guard-led offenses — Damian Lillard and the Portland Trail Blazers are still trying to find a consistent way to take advantage of that move. Instead of looking at ways the other players on the Celtics could help defeat that scheme, there’s a chance that an aggressive dribble drive could also beat the trap. Again, Thomas and Walker have both excelled at knifing through the paint off the dribble. Their ability to quickly speed past flat-footed defenders makes them tough to guard with a live-dribble.
Two areas where 2016-17 Thomas had a noticeable advantage over Walker’s final year in Charlotte was in Spot-Up and Hand-Off scenarios. Walker’s percentages didn’t hit double digits in either but Thomas was at 13.8 percent (Spot-Up) and 11.1 percent (Hand Off). Though Charlotte added Tony Parker last year and had another secondary playmaker in Nic Batum, Walker still spent the majority of his time with the ball in his hands.
That’ll change in Boston. Not only do the Celtics house better secondary creators (Gordon Hayward, Marcus Smart, and Tatum), Stevens’ offensive philosophy calls for multiple players to initiate the offense.
In exchange for having the ball less, Walker will likely see more catch-and-shoot opportunities. Walker’s ascension into an all-star came off the back of the fact that he developed into a knockdown perimeter shooter. Since the 2015-16 season, Walker has shot above 35 percent on six-plus 3-point attempts per game — in 2016-17, Thomas shot 8.5 3-pointers per game.
Walker’s improved accuracy from deep will make him a threat to score off the ball just as often as he would on the ball.
A staple of Stevens offense in Boston has been handoffs, Thomas had a knack for curling off the action and attacking downhill immediately as his defender trailed. In James Borrego first year as the Hornets’ head coach Charlotte saw more motion-based sets implemented in their offense. A former San Antonio Spurs assistant coach, Borrego more than doubled the number of handoff possessions Walker was involved in (77 in 2017-18 compared to 162 possessions in 2018-19 according to Synergy). As opposed to blowing by his defender as we saw in the dribble penetration video, the handoff makes it so that Walker (and Thomas) received the ball already at top speed with an easy decision to make: pull-up if the defender sinks or drive if the defender is too aggressive on the exchange.
Finally, there’s one final factor that Thomas experienced in Boston that Walker hasn’t had the benefit of in Charlotte, transition offense variation. While the Synergy numbers show that Walker had a 0.1 percent advantage in transition frequency, the manner in which each predominantly played in transition were vastly different.
For Walker, the bulk of his transition opportunities were born through him attacking defenders as they retreated. Out of the 330 transition possessions Walker was involved in last season, 245 of them came with Walker as the ball-handler according to Synergy.
In 2016-17, Thomas had 308 transition possessions and only 199 of them were at ball handler. Thomas registered double-digit possessions in every other transition play type too (Leak Outs, First Middle, Left Wing, Right Wing, and Trailer) and was above 20 in three of the five categories. Walker was below 20 possessions in four of the same five categories.
Danny Ainge has been hailed as one of the best executives in the NBA. If you look back at his track record of swindling other general managers in big trades (getting Kevin Garnett out of Minnesota, swapping Jeff Green for Ray Allen, dealing Garnett and Paul Pierce on their last legs for a bounty of future draft assets, trading the number one pick — what became Markelle Fultz — for the third overall pick — Jayson Tatum) it is easy to see why he’s held in such high regard.
A big part of sustaining that greatness is recognizing when things aren’t working out. In a vacuum, nearly every team would trade Thomas for Irving. Yet, NBA franchises don’t operate in vacuums. Moving on from Irving might not have ended up being Ainge’s decision but when faced with the task of replacing the all-star point guard, Ainge believes that reverting back to a player more like Thomas than Irving is the best-case scenario.
It also doesn’t hurt that Walker has been a much more serviceable defender than Thomas over his career. While hard to quantify statistically, Defensive Player Impact Plus/Minus (D-PIPM)is a serviceable estimate of the value a player provides on that end of the floor. Courtesy of Bball Index, Thomas’ career D-PIPM is -1.98 — Thomas has never recorded a positive D-PIPM in a season. Walker’s career D-PIPM is +0.04 with four positive D-PIPM seasons (a career-high +2.1 coming in the 2013-14 season).
While the addition of Walker might be a new face, in actuality, Boston has had a player like him before in Thomas. The Celtics were highly successful in Thomas’ two full seasons and are looking to repeat those finishes as the first or second seed in the Eastern Conference. Walker should enjoy similar opportunities overall that he grew accustomed to with the Hornets while being surrounded with better teammates and not being the lone all-star caliber talent on the roster. Ainge is betting — and betting big — that another Thomas type of point guard (with improved defense) is the key to unlocking the full potential of the Celtics.