5. Willie Upshaw (12.7 bWAR)
Upshaw was an important player in the franchises history. He made his debut in 1978, just one year after the Jays joined the league as an expansion team. He later got more consistent playing time and became one of the earliest Jays to play 1B, which he would go on to do for 9 seasons. Upshaw's slash line with the Jays was .265/.336/.426 with an OPS+ of 104. He hit 112 home runs and drove in 478 runs as a Jay. While they may not appear the most extraordinary numbers on the surface, Upshaw signified a new beginning for the Jays, and was one of their most recognizable players from the team's earliest era.
In addition, Upshaws prime with the Jays had some great years, where he was one of the most valuable players on the team. He finished top 16 in MVP voting in back to back seasons in the mid 80's as one of the better first basemen in the league. He was tied for 8th (with Rance Mulliniks) for most games played in the Jays' history at 1115, so it only felt right to include such a long term player, who was able to contribute in an important way as one of the best 1B the Jays ever had.
Upshaw wasn't the first Jay to ever play first, that honor goes to John Mayberry. He also never had such an explosive stretch as other Jays that would succeed him. But his presence ranging from the dark days of the team's early conception to the "Drive of '85" makes him a key Blue Jay for life, and deserving of starting off this list.