Sanchez suffered the injury on his pitching hand, according to Sportsnet's Ben Nicholson-Smith.
The Blue Jays haven't said whether the starter will miss any time with the ailment.
Sanchez threw 59 pitches before his exit, allowing two hits, an earned run, and three walks in four innings.
The issue is a familiar one for the 26-year-old, who's only made 28 starts over the past two seasons due to finger problems.
Sanchez had been pitching well entering Sunday, posting a 2-1 record with a 2.86 ERA and 4.42 FIP in 22 innings.
The potential loss of Sanchez would test Toronto's starting pitching depth. The Blue Jays placed Matt Shoemaker on the 10-day injured list with a left knee sprain Sunday and are already operating without Clayton Richard and Ryan Borucki, both of whom are out with injuries.
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