As the song says, breaking up is hard to do.

For listeners tuning in to Mike & Mike (which still airs in Philadelphia on 610 WTEL), the show sounds little different from the way it has for the past 18 years. Despite ESPN's plans to split Mike Greenberg and Mike Golic later this year, the two have kept their show going with the lukewarm takes and unoffensive humor that have become its trademark.

But off the air, the relationship between the two has deteriorated to the point that some are speculating the show could end earlier than planned. Sports Illustrated's Richard Deitsch spoke to multiple ESPN staffers who have or had roles on Mike & Mike, and they all painted a picture of a fractured relationship in which the two hosts practically ignore each other on the set.

The rift reportedly began over Greenberg's decision to pursue his own morning show on ESPN, a move that surprised Golic, who apparently first learned about it from Deitsch's reporting last year.

"It's really a poisonous atmosphere right now," one longtime ESPN staffer who has worked on the show told Deitsch. "But I give both these guys immense credit because when the light comes on, you would not know what's going on. They are pros on air."

ESPN expert James Miller, author of Those Guys Have All the Fun: Inside the World of ESPN, noted last week that rising tension between Greenberg and Golic was inevitable.

There was also the ESPN upfront, the network's annual presentation to advertisers. Greenberg was a featured star in the event, where he briefly interviewed tennis superstar Serena Williams. Golic did not appear on the stage.

ESPN declined to comment on the reported feud, confirming only that "Mike & Mike will continue into the fall." Neither Greenberg nor Golic responded to a request for comment.

Some of the frustration between the hosts has bubbled over publicly. Last week, the two addressed the worst-kept secret in sports media on their show for the first time. While Greenberg largely stuck to the script about how wonderful his experience on Mike & Mike had been, Golic sounded a little bit disappointed.

"The last year-and-a-half has been somewhat interesting if not eyebrow-raising, as well," Golic said. "For me, it's not my story to tell. I'm going to continue doing this exact same show. It's for others to tell who made this decision if they want to tell it and how they want to tell it."

One thing that stands out watching the video again is the fact that neither host seems to acknowledge or congratulate the other.

ESPN is moving Greenberg off the show to launch a new morning show for the network. The untitled show is scheduled to premiere on Jan. 1, 2018 and will air live daily from New York City from 7 to 10 a.m. Along with the move, Greenberg signed a new deal with ESPN reportedly worth $6.5 million a year.

Trey Wingo, who anchored ESPN's NFL draft coverage in Philadelphia in place of the semi-retired Chris Berman, will be Golic's new co-host in the yet-to-be-named replacement for Mike & Mike. The show will debut later this fall and will initially be simulcast on ESPN2 before moving to its permanent simulcast home on ESPNU. Golic's son, Mike Golic Jr., will also join the show daily for an hour from 6 to 7 a.m.

Golic's other son, Jake, didn't hold back his opinions on the moves made by ESPN.