The Boston Celtics and Dallas Mavericks are preparing to engage in what should be an incredibly entertaining NBA Finals, and former NBA big man and current ESPN analyst Kendrick Perkins has specified what he thinks is the biggest factor that will determine the series.

The health of Celtics star center Kristaps Porzingis.

Porzingis suffered a calf injury during Game 2 of the Celtics' first-round win over the Miami Heat and has been sidelined ever since. All indications are that he will return for the finals, and possibly as soon as Game 1.

Perkins makes a great point.

The presence of Porzingis can absolutely swing the pendulum of this series. If he is healthy, it's simply hard to imagine anyone beating Boston, including this red-hot Mavericks team. But if he doesn't play or if he plays and is extremely limited, the C's will be very vulnerable to Luka Doncic and Co.

This series probably means a little extra for Celtics' Kristaps Porzingis

Boston Celtics center Kristaps Porzingis (8) makes the basket against the Dallas Mavericks in the second half at TD Garden.
David Butler II-USA TODAY Sports

If there were any series that Porzingis would really want to play in no matter what, it's probably this one.

Remember: Porzingis began his career with the New York Knicks, but he was traded to Dallas in the middle of the 2018-19 campaign. He didn't play at all that season as a result of recovering from a torn ACL, but he made his Mavericks debut the following season.

The 28-year-old posted impressive numbers for the Mavs in two-and-a-half years of play time there, but he didn't quite mesh with Doncic. Plus, injuries to Porzingis really limited Dallas' potential in the playoffs, leading to the Mavericks sending him to the Washington Wizards midway through the 2021-22 season.

The Celtics then acquired Porzingis in a three-team trade last summer.

Dallas did not believe Porzingis was the answer, and he and Doncic did not see eye to eye. Do they dislike one another? Maybe, maybe not. Neither has said anything negative publicly, but you kind of get the feeling that Porzingis may harbor some ill will toward his former teammate and franchise.

Porzingis may be injury prone, but he is far from soft. He plays with an edge, so it would not be surprising if he takes things personally. For example, look at how well Porzingis plays whenever he goes back to Madison Square Garden and hears boos from Knicks fans. He seems to thrive off of that.

So, perhaps this extra juice is exactly what Porzingis needs to get back on the floor and produce.

The former No. 4 overall pick played in 57 games for Boston this season, averaging 20.1 points, 7.2 rebounds and 1.9 blocks over 29.6 minutes per game. He shot 51.6 percent from the floor, 37.5 percent from three-point range and 85.8 percent from the free-throw line. He also logged a career-high .226 win shares per 48 minutes.

Porzingis is incredibly value on both ends of the floor, and his well-being will absolutely be the most crucial X-factor of this upcoming series.

If Porzingis is even close to 100 percent, the Celtics are going to be very difficult to solve.

It's just one of the many fascinating storylines heading into the NBA Finals.