McCallum has been granted a release from the B.C. Lions, who asked the kicker to retire five days into their training camp.
"I don't usually do this but I want it to be very clear! I did not ask to be released! I was told to retire or I would be cut," McCallum tweeted on Saturday, two days after he left training camp for "personal reasons."
The upcoming CFL season would be No. 23 for McCallum. He's played 11 with the B.C. Lions. Last season, the 45-year-old McCallum hit 38-of-42 field goals for a league-best 90.5 per cent success rate.
McCallum has the second most points in CFL history, behind former Lions kicker Lui Passaglia. He also has played in the the sixth most games in league history,
"Paul and I have had ongoing discussions over the past number of seasons regarding his future with the club," Lions' GM Wally Buono said in a release. "In keeping with what Paul and I discussed, the club will grant his request for a release at this time.
"We appreciate his many contributions to our organization and we wish him the best moving forward."
Both Buono and head coach Jeff Tedford have said they want kickers who can do all three — place-kicking, punting, kickoffs.
The Lions have a pair of impressive 23-year-old kickers in Richie Leone and Anthony Fera at camp.