Tom Welling is introduced as Mary's father, Samuel Campbell, in TVLine's first look at The Winchesters Season 1 Episode 7.
Mitch Pileggi played Samuel in Supernatural Season 4 when Dean travelled back in time to 1973. The logline for Episode 7 reads, "the hunt heats up, and Mary and John find trails that lead back to their fathers."
While The Winchesters has a fresh cast, numerous Supernatural alumni appear, including Jensen Ackles reprising his role as Dean, Richard Speight Jr. playing his part as Loki, and Gil McKinney reprising his role as Henry Winchester.
Tom Welling's Appearance on The Winchesters Season 1 Episode 7 Sparks Breaking Canon Fears
Supernatural fans have questioned the prequel for not sticking to Supernatural canon since it was first pitched by Ackles, who is also an executive producer on the series.
While The Winchesters delve more into John and Mary's early years, their lives were also touched upon in Supernatural, which presents a vastly different story than the prequel.
The Winchesters begin in 1972, with Mary's family driven apart as she searches for her missing father. She does this with the help of John, who joins her as a hunter. In Supernatural, however, John did not become a hunter until after Mary's death in 1983.
Given these alterations, there's a chance that Welling's portrayal of Samuel on The Winchesters, which previously covered part of his whereabouts in the 1970s, would further disrupt the Supernatural canon.
The Winchesters Creator Reassures All Loose Ends Will be Tied
Despite concerns that The Winchesters will diverge drastically from the original series, producer Robbie Thompson has assured fans that the spinoff will be perfectly connected to Supernatural. Though the specifics are yet unknown, Thompson stated that the 13th and final episode would clarify the connections between the two shows.
Some fans speculate that this could mean time travel, parallel universes, or demonic possessions, all of which have already appeared in Supernatural. However, after only six episodes, The Winchesters has altered much of Supernatural's canon. This features Mary and John getting along right away, John learning about the supernatural world, and John learning about his Men of Letters history.
However, there is still plenty of time for questions to be resolved, and Welling's portrayal of Samuel in The Winchesters Season 1 Episode 7 will significantly advance the plot, even though it may further deviate from Supernatural canon.