Baseball purists were outraged when Bud Selig and Major League Baseball introduced interleague play during the 1997 season. The casual fan however relished the opportunity to witness new and unfamiliar matchups. Interleague play also made possible head-to-head series between cross-town rivals in large cities, with series like Cubs vs. Sox, Dodgers vs. Angels, and Mets vs. Yankees drumming up excitement and increasing ticket sales league-wide.

Recently however, baseball experts have begun to speculate that the novelty of interleague match-ups has worn off, and fans are tiring of the spectacle. Said ESPN senior baseball writer Rob Neyer on ESPN Radio: “I just think it’s overdone. I would love to see interleague play be limited to maybe 6 games per season…i think nobody is excited about the Royals and the Rockies, or the Padres and the Mariners.”

However, with all due respect Mr. Neyer, empirical data proves otherwise. The best way to gauge fan excitement is through how much they are willing to pay for a ticket to an individual game, and despite your speculation to the contrary, fans actually are excited about seemingly uninteresting interleague matchups. Tickets for the Saturday game of the aforementioned Mariners-Padres series were trading at an average price of $71.29, almost ten dollars higher than that day’s lone National League matchup featuring the tied for first place St. Louis Cardinals, which are selling for $61.79.

Utilizing Seatgeek’s unique database of secondary market ticket transactions, we compared prices of June interleague matchups, to the prices of the National League game taking place on the same day, thereby eliminating the day of the week as a confounding variable. Our findings, based on millions of dollars worth of transactions, show that the average cost of a ticket for an interleague game in June is $101.51. This is almost double the NL average of $51.27. Additionally, the average price for a ticket to the most popular interleague game, the Friday June 18th clash between the Yankees and the Mets, was more than three times the cost of a ticket to the most popular National League game, the Wednesday, June 23rd match between the Astros and the Giants, at $209.10 to $62.59.

Almost all interleague games are trading at higher prices than their N.L counterparts. However certain series are more popular than others. The top 5 most in demand series are, unsurprisingly:

For tickets and price forecasts to these games and more, don’t forget to visit seatgeek.com.

Update: Interleague Play in Review 6/29/10

As the interleague matchups have drawn to a close for the 2010 season, we decided to take a retrospective look back at this year’s results, both on the field, and off. Once again the AL emerged from interleague play victorious, going 134-118, and winning the majority of contests for the seventh straight year. Teams such as the Boston Red Sox (13-5 in Interleague play) and Chicago White Sox (15-3) used their interleague supremacy to catapult themselves back into their respective divisional races, while the Texas Rangers solidified their lead in the AL West, by going 14-4 against National League opponents. Certain players embraced interleague play with open arms as well. Jake Peavy, who has struggled since his acquisition by the White Sox, posted a microscopic 0.78 ERA during this stretch, and Rangers’ outfielder Josh Hamilton hit .472 during interleague games.

While inevitably at this time of year baseball purists, writers, bloggers, and fans alike express their disdain for the “artificial” rivalries created by interleague games, as we previously proved, Interleague play sells! Now, as all regular season AL – NL matchups have concluded, we can reflect on just how well interleague play resounded with fans in 2010.

As it turns out, fans quite enjoy watching Interleague games, regardless of their “artificial” nature. As we have shown in a recent blog post, ticket sales are correlated to fan support. Major League Baseball announced yesterday that attendance for interleague games was up 17.8% over 2010 intraleague matchups, drawing an average attendence of 33,253 fans per game, compared to the intraleague average of only 28,233. Our friend Maury over at bizofbaseball.com recently released a comprehensive review of attendance at interleague games which I highly recommend. According to his analysis, the top interleague park in 2010 was Dodger Stadium, drawing an average attendance of 54,332 in 6 games against the Yankees and Angels.

We also decided to take a quick look at the top selling games during this time period. Between the dates of May 21st, the first day of Interleague play, and June 27th, the last, there were 512 MLB games, of which less than half, 252, were interleague, and 260 were intraleague. However, despite being the minority of contests, the top 10, and 14 of the top 15 highest priced games during this time period were of the interleague variety.

The top-selling game, perhaps unsurprisingly, was the Saturday May 22nd Subway Series clash between the Yankees and Mets at Citi Field. Rounding out the top 5 are more of the usual suspects when it comes to drawing high ticket prices, including the Dodgers, Red Sox, and Phillies in addition to the Yankees and Mets.

During his same interview on ESPN radio, Rob Neyer concluded: “The reason it is the way it is now, is because this is the way it was conceived by Bud Selig…16 years ago, and we’re stuck with him until he’s not commissioner anymore, but I guarantee you in five to ten years it won’t be like this.” Well in this instance we have to admit you’re right Rob. If these current ticket trends continue, in five to ten years we most likely will not have teams playing 18 interleague games a season. They’ll be playing many, many more.

You can listen to Neyer’s interview here.

For more data or to answer any questions or comments, email me at jonathan@seatgeek.com and follow on twitter @SeatGeekMLB