A simulcast of Philadelphia radio personality Michael Smercon ish’s show will fill the old Don Imus timeslot on MSNBC next Monday through Wednesday.

An MSNBC official said there will be a “variety of fill-ins” used on the 6-9 a.m. slot where Imus’s radio show was simulcast before he was fired by NBC and then by WFAN.

Smerconish, a morning-drive personality on talk-radio station WPHT (1210 AM), is no stranger to MSNBC. He’s subbed for “Scarborough Country” host Joe Scarborough nine times and has appeared on “Dayside” three times.

Smerconish said on his radio show yesterday that his guests on Monday will include Jackie Mason and MSNBC’s Chris Matthews.

MSNBC has been using in-house talent, including NBC’s chief White House correspondent, David Gregory, to fill the 6-9 a.m. slot – and officials say that will continue for the foreseeable future.