In mid-July of 2019, Porzingis signed a contract with the Mavericks. His 2019-20 campaign would mark his first with a new team after playing for the Knicks -- the team that drafted him. He did not participate in the 2018-19 season due to recovery from a torn ACL, so when Porzingis made his team debut Oct. 23, it was his first taste of NBA action since Feb. 6 of 2018. During that debut, Porzingis recorded 23 points, four rebounds, two assists, one steal and one block in 29 minutes against the Wizards. Two games later, he recorded his first 30-point game of the season, finishing with 32 points, nine rebounds, a career-high five assists and two blocks in 34 minutes against the Trail Blazers. Two days later, the big man posted his first of 25 double-doubles, dropping 10 points, 14 rebounds, three assists and two blocks in 33 minutes against the Nuggets. Shortly after, on Nov. 3 in a win over the Cavaliers, Porzingis blocked a season-high six shots in addition to posting 18 points, nine rebounds and one steal in 31 minutes. On Dec. 20 in a win over the 76ers, Porzingis recorded a career-high 18 rebounds in 37 minutes, in addition to 22 points, three blocks and one steal. Porzingis swiped a season-high three steals during a 25-point win over the Grizzlies on Mar. 6, also contributing 26 points, 11 rebounds, four assists and four blocks in 29 minutes. Porzingis' career-high seven made threes occurred during the NBA bubble on Aug. 11 against the Trail Blazers. He finished that contest with 36 points, six rebounds and two blocks as well. Arguably Porzingis' best all-around performance of the campaign was Mar. 1 in a 20-point win over the Timberwolves, with the 24-year-old recording 38 points (13-25 FG, 6-14 3Pt, 6-10 FT), 13 rebounds, five blocks, four assists and one steal. Due to a knee injury, Porzingis was only able to appear in three of the team's six playoff games against the Clippers. In those appearances, he averaged 23.7 points, 8.7 rebounds and 1.0 blocks in 31.5 minutes.

Porzingis sat out the entire 2018-19 season due to the torn ACL he'd suffered the year before. However, that didn't mean he stayed entirely out of the headlines, as the Knicks traded him to Dallas on Jan. 31 for a package of draft picks and expiring contracts. Following the season, Porzingis signed a five-year agreement with the Mavericks.

Porzingis got off to a huge start to his third NBA season, only to have his year cut short by a torn ACL in February. However, he had plenty of time for highlights before that. The Latvian big man played in 48 games, averaging a career-best 22.7 points per game. Had he qualified, that figure would have ranked 13th in the league. He also set career highs in threes per game (1.9) and blocks per game (2.4, which would have been second in the NBA if he'd qualified). For the second straight year, Porzingis boosted his efficiency from long range, connecting on 39.5 percent of his threes. He contributed plenty of rebounds, too, averaging 6.6 per game. He started the season on fire, scoring 30-plus points in four of the first five games, including a pair of double-doubles; he went on to record five on the season. On Nov. 5, he posted the first 40-point game of his career, going 15-of-24 from the field while adding eight rebounds and six blocks against Indiana. Porzingis was named to his first All-Star team, though he was unable to play due to his injury.

Porzingis built on his incredible rookie season with an even better sophomore year in 2016-17. Although he was limited by injury to 66 games (65 starts), he lifted his scoring average to 18.1, thanks in part to better shooting -- his field-goal percentage improved to 45.0 and his success rate on threes ticked up to 35.7. He also raised his shot-blocking average to an even 2.0, finishing fifth in the NBA in that category, and was again strong on the boards with 7.2 per game. The 21-year-old Latvian racked up 26 games with at least 20 points and cleared 30 on three occasions. His biggest offensive performance came Nov. 16 against Detroit, when he racked up 35 points on 13-of-22 shooting. On Dec. 11, Porzingis tied his career high with seven blocks in a 26-point, 13-rebound double-double against the Lakers. Two days later, he went off for 34 points against Phoenix, including going 4-for-4 from downtown -- one of eight times that he hit four threes in a game. All told, he racked up 12 double-doubles. That included tying his career high with 15 rebounds alongside 24 points against Golden State on Mar. 5. He also won the Skills Challenge at All-Star Weekend.

The Knicks spent the No. 4 overall pick on Porzingis in the 2015 NBA Draft, and he paid immediate dividends. Over the course of 72 games, the Latvian rookie averaged 14.3 points, 7.3 rebounds and 1.9 blocks, finishing second only to Carmelo Anthony on the team in scoring and rebounding while leading the club in rejections. He racked up 20-plus points on 14 separate occasions, including a season-high 29 twice. Porzingis double-doubled in both of those games -- and 21 times overall on the season He set his high-water mark in rebounding Nov. 11, pulling down 15 boards against the Hornets. Already a master shot blocker, Porzingis recorded multiple blocks 38 times and notched seven on two occasions. All told, he finished eighth in the NBA with 134 total blocks. His well-rounded skill set also included strong 3-point shooting -- he made 1.1 threes per game at a 33.3 percent clip -- and an 83.8 free-throw percentage. In the Rising Stars Challenge during All-Star Weekend, he racked up 30 points for Team World. Porzingis was named Rookie of the Month three times (October/November, December and January) and finished second only to Karl-Anthony Towns in the Rookie of the Year voting, making the NBA All-Rookie First Team in the process.