The young Raptors star, who recently returned from an injury layoff, has jumped Philadelphia 76ers’ Joel Embiid, who is currently sidelined with a hand injury.
Siakam had been ranked third in the first two vote returns released by the NBA.
Siakam leads Embiid by just over 34,000 votes, although he trails the Milwaukee Bucks’ Giannis Antetokounmpo by over two million votes for the top spot in the third returns released by the NBA on Thursday.
Three frontcourt players will be voted in as All-Star starters. Should Siakam be chosen, it would be his first All-Star Game selection.
The Raptors have had at least one player voted into the All-Star Game for five consecutive seasons. Kyle Lowry was chosen in 2015 and 2016, DeMar Derozan in 2017 and 2018, and Kawhi Leonard in 2019.
Lowry is currently fifth among Eastern Conference guards with 848,293 votes. Fred VanVleet sits 10th with 546,471.
Trae Young of the Atlanta Hawks leads the jammed guard race with just over two million votes. Less than 300,000 votes separate Young, second-place Kyrie Irving of the Brooklyn Nets, and third-place Kemba Walker of the Boston Celtics.
In the West, LeBron James and Luka Doncic both hold sizeable leads at their respective positions.
Doncic is first among west guards with 4.5 million votes, 1.6 million ahead of second-place James Harden, who has a two million-vote cushion on third-place Damian Lillard.
James and teammate Anthony Davis currently hold down the top two spots among west frontcourt players with 4.7 and 4.4 million votes, respectively. Kawhi Leonard sits a ways back in third with 2.9 million.
The All-Star starters are chosen by a combination of fan, player and media votes, with the fan votes accounting for 50 per cent of the total. Three frontcourt players and two guards are chosen as starters for each conference.
The top vote-getter in each conference will be named captain. Antetokounmpo is almost certain to be named captain of the Eastern Conference All-Stars with a two million-vote lead over Siakam. James currently leads Doncic by 150,000.
Voting closes at 11:59 p.m. ET on Jan. 20. The starters will be announced on Jan. 23. The captains will choose their teams on Feb. 6 and the All-Star Game takes place on Feb. 16 at the United Center in Chicago.