The Celtics will enter training camp in a couple of weeks with no clear fifth starter. Though Joe Mazzulla could technically go small with another guard next to Derrick White, Jaylen Brown and Jayson Tatum, all signs indicate the team plans to use a bigger lineup with either Al Horford or Robert Williams alongside Kristaps Porziņģis.
But which second big man will Mazzulla choose? It might not be an easy decision. Here are the cases for both.
The argument for Williams: After a season hampered by injuries, his circumstances have turned around. He entered the offseason healthy, which marks a major change from one year ago as knee surgery kept him out of the lineup until mid-December. When Williams is right physically, the Celtics have typically reached their highest level with him on the court. Though he was on a minutes restriction and probably not at his bounciest, the team pummeled opponents by 11.4 points per 100 possessions with Williams on the floor last season. His presence transforms Boston’s defense. That’s why his teammates reacted with such joy when Mazzulla reinserted Williams into the starting lineup during the Philadelphia playoff series.
Put Williams next to Porziņģis, and opponents may not be able to see the rim, much less score on it. The big men each rank among the league’s best interior deterrents. Opponents shot 11.4 percent worse than expected on shots inside of six feet with Porziņģis defending. Williams had a similar effect, holding opponents to 53.7-percent shooting from that range, 9.5 percent worse than expected. The previous season, when Williams was healthier, his defensive numbers at the rim were even more impressive. That type of shot blocking can serve as the foundation for an entire defense. Without Marcus Smart, the Celtics could want to play a bit differently at that end of the court.
And the offense? Well, the Wizards scored relentlessly last season when Porziņģis played next to Daniel Gafford, another rim-running center. With all of the other talent in Boston, a similar frontcourt could be a good formula to maximize everyone. Using a lob threat alongside four shooters is a proven way to put all sorts of pressure on a defense. The Celtics hardly ever grabbed offensive rebounds without Williams on the court last season, but they became competitive in that category as soon as he stepped onto the court. His constant energy could help in a starting lineup that now has three big-time scorers but not as many connective pieces without Smart.
The Celtics were never quite able to unleash Williams last season. After he missed the first two months of the campaign, the team put him on a pitch count of sorts when he returned. He was only able to average 23.5 minutes per game, which Brad Stevens later listed as one of the reasons Mazzulla largely went away from two-big lineups. In large part due to health, Williams simply hasn’t been as dependable as Horford. But Horford is 37 now. He doesn’t rebound at the offensive end of the court and rarely even tries to score inside the arc these days. Last season was the first time his team defended better with him on the bench since 2014-15. Though he still helped tie everything together for the Celtics, per usual, they need to skate to where the puck is going. Horford has already started slipping in certain ways and is not getting any younger. Plus, a guy his age could use a lighter load. The Celtics have another good option to start. Williams, who should be in a much better place physically than he was this time last year, could be set up for a bounce-back season.
The argument for Horford: Does anybody else on the Celtics make the right play more consistently? Horford is almost always in the right spot. He is always unselfish. He is Boston’s best option against the league’s premier low-post scorers — such as Joel Embiid — but can also switch onto some of the league’s quicker guards, even at 37. The Williams-Porziņģis duo is bursting with defensive potential, but the defense could actually be better with Horford next to Porziņģis.
Horford will be one of the oldest players in the league. So what? He remains one of the Celtics’ most trustworthy players. He was far more durable than Williams last season while averaging 30.5 minutes per game. That may be too much playing time for a guy born in 1986, but Mazzulla has room to cut down some of Horford’s minutes while still keeping him in the first unit. The idea of Williams flying for dunks while Porziņģis, Tatum, Brown and White keep the defense occupied is fun, but so is the vision of a starting five filled with nothing but shooting threats. The Celtics thrived with a five-out offense last season and could do the same again – except with one of their guards being replaced by a 7-foot-3 Lithuanian sharpshooter. At the other end of the court, Smart’s vocal leadership will be missed. He was forever pointing at teammates to direct them into the right spots. With him in Memphis, Boston could need to lean more on Horford, another top defensive communicator.
The overall outlook: Assuming the Celtics’ big men all stay healthy (maybe not a safe assumption), Mazzulla will be selecting from two strong options. He could spend training camp experimenting with the different groups to see what works best. No matter who he puts in the first unit on opening night, Boston’s top three big men will probably all miss some time for various reasons (such as the team’s pattern of giving Horford one night off on each back-to-back set). The Celtics will need to be flexible on those occasions.
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