Forsberg: Just how good has Time Lord been with more playing time?

No catch-all metric is perfect in its attempt to determine the best NBA players in a single season, but Player Efficiency Rating tends to be the gold standard (and, at worst, an excellent conversation starter).

The John Hollinger-created metric attempts to determine the most impactful players in the league by combining box score data. Take a look at the rankings two-thirds of the way through the NBA season and it’s hard to quibble that the top three names -- Joel Embiid, Nikola Jokic, and Giannis Antetokounmpo -- are smack dab in the middle of the MVP conversation. The top 20 is basically a shuffled All-Star roster.

Well, except for the player sitting at No. 5.

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That’s where you’ll find Celtics third-year center Robert Williams III and his shimmering 31.31 rating. Now, PER has a way of buffing high-efficiency centers who fill up multiple categories of their box scores. That’s why Atlanta’s Clint Capela and Los Angeles Lakers’ Montrezl Harrell join Williams in crashing the star party.

But Williams’ lofty PER placement underscores just how impactful he’s been in an elevated role, particularly the past two weeks. In five games since shuffling to a starter, Williams is averaging 11.8 points, 10 rebounds, 4.6 assists, 2.6 blocks, and 1.4 steals over 27.3 minutes per game. His average game score -- another Hollinger all-in-one metric that Basketball Reference utilizes to quantify the quality of a performance -- is 18.1, peaking at 28.8 while posting a near triple-double versus the Rockets last week (an average game score is 10).

Yes, the Time Lord is blossoming right before our eyes. He’s provided an infectious energy on the defensive end with his hustle-heavy, shot-altering ways. On the offensive side, the increased playing time has allowed him to showcase his passing skills and the Celtics are slowly increasing how much of the offense flows through him.

It is not a coincidence that Boston has won four of its last five games with Williams in a starting role. Over the last six games overall, the Celtics have a net rating of plus-17.6 in Williams’ 137 minutes of floor time. That includes a sterling offensive rating of 126.4 that is 11.2 points higher than the team’s average in that span.

The Time Lord Hype Train reaches a critical juncture on Tuesday night when the Celtics welcome Embiid and the East-leading Philadelphia 76ers.

In past seasons, the Celtics have done their best to hide Williams in matchups against Philadelphia. He would only typically play in minutes with Embiid off the floor. On Tuesday night, Boston might not have any other choice, particularly if Tristan Thompson remains out while reconditioning as he emerges from health and safety protocols.

This season, Embiid and Williams have matched up for only 55 seconds and a total of 3.2 partial possessions, according to the NBA’s matchup data. Embiid generated 5 points while making his lone field goal and adding three free throws off two shooting fouls in that tiny sample. It is the only regular-season data that exists for the two players over the past three years (Williams did guard Embiid for 1 minute, 25 seconds in the bubble playoffs and was whistled for three shooting fouls in that short span).

The next step in Williams' evolution is showing he can hang -- defensively -- with the best centers in the league. The Celtics can no longer protect him from tough matchups. He’s too valuable to them and how they want to play. Williams has infused energy on both sides of the ball and, even in the darkest times for this team this year, he has provided a glimmer of hope.

Who else can make plays like this …

Time Lord toe-taps like a wide receiver while falling out of bounds then slings a dart to Fournier that would make Cam Newton blush. Williams has always been an above-average passer who’s only fault is sometimes being a bit too eager to get it out of his hands. But his vision is outstanding and his ability to direct the ball through traffic to open shooters has created some outstanding looks lately.

The Dime Lord is a very real thing.

Consider this, in the 25 games since the Celtics first unleashed Williams -- appropriately, it came on Valentine’s Day this year -- Boston has an assist percentage of 59.7 in his 505 minutes of floor time. That’s the second-best mark among regulars in that span, trailing only Marcus Smart. In the 705 minutes without Williams, that assist rate plummets to 55 percent.

For a Celtics team that improbably ranks 27th in the NBA in assist percentage (55.7), this is not insignificant. Getting Smart back from injury has helped juice the assist marks but Williams adds a dynamic as a facilitator in the high post that’s been sorely missing since Al Horford darted for Philly.

Thompson is also an offensive rebound maven but too often he collects a rebound and doesn’t even seem to consider kicking it back out. With Williams, he’s almost instantly trying to give the ball up in hopes of getting a shooter a clean look.

Like this …

After a Jayson Tatum miss, Williams goes over the top of two black jerseys to tap the ball away. Freeze the video as he somehow shifts position and hands while in the process of corralling the ball, and you can see Williams is already looking out at Kemba Walker beyond the 3-point arc. Williams gathers the rebound and delivers a two-handed bullet with no one within 10 feet of Walker, who calmly drains the 3-pointer.

Not even PER can quantify moments like that. Williams has an underrated basketball IQ and his unselfishness makes his teammates that much more dangerous. He’s content to subsist on lobs around the basket, or muscling home tough finishes when driving teammates throw it his way as a bail-out option.

The challenge for any player as their star starts to rise is to keep finding ways to improve and not become complacent with their success. Williams has said all the right things, often praising teammates for “making me look good.” His talents are undeniable but even he acknowledges that everything starts on the defensive end. And the next step is being able to hold his own in challenges against players like Embiid.

Tuesday night’s showdown with the Sixers won’t just provide a litmus test for where these Celtics stand after some positive signs in recent games. But we’ll see just how far Williams has come with his opportunity the past two months.