The striker is looking to get some crucial pre-season fitness work under his belt as he looks to work his way back from a hernia problem, but his omission in midweek could now delay his return to competitive action.
Manager Alan Knill had hoped to have Morrell and fellow marksman Andy Bishop, who is also recovering from a double hernia operation, back in time for the second week of the season.
But he admits the club will just have to wait for them to regain full fitness with one-month loan options out of the window.
Speaking after Bury's 2-1 defeat at Fleetwood, which he hopes will be a "wake up" for the new campaign, he told the club's official website: "They're not available for a month. A striker, other clubs don't want to let them out for a month, it's no good to them, no good to the club.
"We've had a couple of players for six months but then we can't afford that, so it's difficult. It looks like we'll just have to ride it out for now and see."