It appears the only constant in Philadelphia sports radio is change.

At 94.1 WIP, current evening host Jon Marks will replace departing talker Chris Carlin as the station's new drive-time host and pair up with former Eagles linebacker Ike Reese. Marks' first day on the new show will be Thursday.

The hole in WIP's lineup was forced by Carlin's coming move to sister station WFAN in New York City, where he will join former Jets linebacker Bart Scott and SI Now host Maggie Gray. The new three-person show will replace that of longtime sports radio host Mike "The Sports Pope" Francesa when he retires on Dec. 15.

On Tuesday's show, Carlin briefly announced the news before leaving the show after just 10 minutes, replaced somewhat awkwardly by longtime WIP host Glen Macnow (who will also guest host on Wednesday). Before departing, Carlin thanked Reese and WIP listeners for caring about the thoughts of a "dope from New York."

"The knock that Philly gets nationally is so beyond stupid," Carlin said. "My respect level for this town is off the charts." sports writer Joe Giglio will take over the evening hosting chair vacated by Marks. For Giglio, who has spent four years at WIP as fill-in host, it's his first shot at hosting his own regular show. He will also start his new post Thursday.

Marks joined WIP back in February after surprising everyone by walking away from the 97.5 The Fanatic morning show he co-hosted with Anthony Gargano. Marks' time at The Fanatic went all the way to 2005, when he started as an intern when WPEN first became a sports station in 2005 (as Sports Talk 950 AM). He has been hosting WIP's evening show for the past nine months.

Marks, who worked for four years as producer for 97.5 The Fanatic's Mike Missanelli, now finds himself directly competing with his former colleague. Missanelli remained safely ahead of Carlin and Reese in the 2017 summer ratings book, but the WIP duo did narrow the gap by increasing its ratings 22 percent in the coveted demographic of men age 25 to 54 compared to the same period last year. It'll be interesting to see if Marks can continue that trend, or if Missanelli will pull away.

Since Carlin was hired by WIP last year to replace the fired Josh Innes, there have been persistent rumors that he was in Philadelphia only as a warm-up to replace the retiring Francesa, for whom Carlin once worked as a producer. According to sources, the move was forced on WIP by WFAN after morning host Craig Carton resigned following his arrest in September on investment-related fraud charges,

"No one brought up the idea when I decided to go for the job in Philly," Carlin told me last year. "For me, this is my time."

The only shoe that has yet to drop is who will be replacing Carton alongside former Bengals quarterback Boomer Esiason on WFAN. Newsday's Neil Best reports the leading candidate is CBS Radio host Gregg Giannotti, who has been guest-hosting most mornings.

One thing we know for certain: It won't be Gov. Chris Christie, who the station made clear was dropped from its pool of candidates.