The EFL this week released registered squad lists in line with salary cap rules, where a maximum of 22 players – not including those aged under 21 – can be named to play league action.
Town’s list, which can be viewed here, features just 21 names and does not include that of Clarke, 36, a high-profile striker signed by former boss Sam Ricketts in September.
Former Wolves man Clarke has been struggling with a hamstring injury and stand-in boss Wilbraham said manager Steve Cotterill made the call to leave one registration space in the squad available, in case Shrewsbury suffered more defensive injuries and were forced to bring in a free agent as emergency cover.
“When the squad had to be named Clarkey was injured and obviously has had a couple of injuries this season,” Wilbraham said.
“With the centre-half situation, there was no reason to name Leon is the squad, with him injured, because there were so many centre-halves injured.
“If we would’ve had another injury to a centre-half it might have been that we’d have to sign a non-contract defender.
“It’s by no means that Clarkey’s been left out the squad and I’m sure in due course the manager will make that decision whether Leon comes back into it.
“As the defenders are getting back fit, it’s more than likely that’ll happen. But there was no point putting a player in who was injured and not back for a certain amount of time when we were down to the bare bones at centre-half.
“If we’d got another injury it might have been out of our hands to have to get a non-contract defender.
“If there were three strikers injured at the time it might have been the centre-half left out until we knew what was going on with the strikers, the situation came up.”
Town are missing Aaron Pierre (calf), Matthew Pennington (shoulder) and Brad Walker (ankle), meaning only Ethan Ebanks-Landell and Ro-Shaun Williams are left as recognised senior centre-backs.
Earlier in the season, former boss Ricketts elected not to register full-back Donald Love or midfielder Sean Goss in the league squad, under the new rules introduced for the current campaign.
The squad list does not feature the likes of youngsters Nathanael Ogbeta, 19, Ryan Barnett, 21, or any Salop player born on or after January 1, 1999.
Barnett will now return to Town from his loan at National League North Gloucester City, whose season was last night declared null and void.
Irishman Josh Daniels is the only player in Town's squad list who does not fall under the EFL's 'homegrown' category rules, of which there must be at least eight in the registered squad.
Town registered squad list in full (* 'homegrown player'):
1 - Burgoyne, Harry *
2 - Chapman, Harrison *
3 - Daniels, Joshua
4 - Davis, David *
5 - Ebanks Landell, Ethan *
6 - Edwards, David *
7 - Golbourne, Scott *
8 - Goss, Sean *
9 - Love, Donald *
10 - Main, Curtis *
11 - Norburn, Oliver *
12 - Pennington, Matthew *
13 - Pierre, Aaron *
14 - Pyke, Rekiel *
15 - Sarkic, Matija *
16 - Sears, Ryan *
17 - Udoh, Daniel *
18 - Vela, Joshua *
19 - Walker, Bradley *
20 - Whalley, Shaun *
21 - Williams, Ro-Shaun *