A day after Sports Illustrated announced [0] that it had reached a partnership deal with longtime ESPN anchor and radio host Dan Patrick, group editor Terry McDonell announced late Friday that the magazine’s most popular columnist, Rick Reilly, would be leaving the magazine to join ESPN.

Reilly, who has been with Sports Illustrated for 22 years, will leave the magazine after his contract expires in November. In a note to SI staffers, McDonell wrote that Reilly would be leaving to pursue “television interests.”

The resulting trade in high-profile columnists is the latest shot across the bow in a bitter battle over talent between SI and ESPN.

According to popular sports blog The Big Lead [1], Reilly will have to wait until next June—when his non-compete clause expires—to start at ESPN.

Patrick will join Sports Illustrated in January as a senior writer. As part of what purports to be a highly synergistic partnership, Time Inc. also said that its digital unit will host Patrick’s radio show on his Web site, www.danpatrick.com [2].