The Houston Astros came into their Wednesday night game as a massive favorite, but the Detroit Tigers stunned Justin Verlander to pull off a 2-1 upset victory over the leading World Series contender.

Detroit Tigers Astros Upset
The Detroit Tigers pulled off the biggest upset in recent MLB history by beating the Astros 2-1 on Wednesday. (Image: David J. Phillip/AP)

The result produced the largest MLB betting upset in at least the last 15 years.

Second Massive Upset of Astros in August

Most sportsbooks had the Astros as at least a -550 pick to get a win on Wednesday, with FanDuel Sportsbook listing Houston at -600 by the time the game began. That meant big money for bettors who were willing to put some money down on the Tigers, who went off at +435 at Caesars Sportsbook.

That beat the record for the highest odds paid out by Caesars on any single MLB game in the past 15 years. The previous high came in 2007, when the Nationals beat the Twins at +395 odds.

The record was almost broken 10 days earlier, when the Astros were upset by another last-place team. The Baltimore Orioles beat Houston 8-7 as a +390 underdog, which now stands as the third-largest upset on record.

Big favorites often attract lots of action from bettors, often as a way to add a small amount of value to a parlay. Mirage/MGM sportsbook shift manager Scott Shelton told ESPN that he saw a $55,000 bet on Houston to win at -550 odds, and a $63,520 bet on Houston at -575.

Sportsbooks also took plenty of action on the run line, with Houston going off at more than -200 even when giving up 1.5 runs.

Tigers Use Two Solo Shots to Stun Verlander

The extreme odds were justified. The Astros came into the game with an 81-46 record, third-best in the majors. Meanwhile, the Tigers were 37-86, which was the worst mark in the league. Houston was also sending Justin Verlander to the mound, who leads the American League in innings pitched (178.2) and ERA (2.77).

Verlander predictably held the Tigers to just two hits. But both were solo home runs, and the Astros offense largely came up empty in the 2-1 loss.

“That’s the biggest win for us in a long, long time, especially against a premium team like that, a World Series contender and Verlander on the mound,” Tigers manager Ron Gardenhire told reporters after the game.

The loss didn’t go over well with Verlander, who requested that Detroit Free Press reporter Anthony Fenech be blocked from his postgame media session. The Free Press reported that Fenech was indeed prevented from attending by Astros security, a move that was against Baseball Writers’ Association of America protocol, and may also have violated the MLB collective bargaining agreement.

Large upsets are unusual in MLB betting, mainly because large mismatches are uncommon at the major league level. In a sport where even the worst teams of all time have won a quarter of their games, even the worst possible matchup has plenty of uncertainty. In fact, ESPN reported that over the past 15 seasons, there have been only 19 underdogs of at least +345, and those teams have a 10-9 record.

The Tigers will have a chance to add another major upset to the record books on Thursday. With Gerrit Cole on the mound, Houston is a -550 favorite at DraftKings, with Jordan Zimmermann and Detroit coming in as a +430 underdog.