Their series price against sixth-seeded Minnesota moved from about -3000 pre-series to -200 after a 104-102 defeat and Anthony Edwards' return from a knee injury.
The report says the adjustment may be an overreaction, arguing San Antonio still has superior depth and should recover to beat the Timberwolves in six games.
If Minnesota wins, it would rank among the biggest NBA playoff upsets, with no comparable second-round underdog of +1000 or longer found by the analysis.
After Minnesota's stunning Game 1 win, are the Spurs now the biggest value bet of the playoffs?
Why are pro bettors wagering millions on the Lakers despite their historic underdog odds against the Thunder?