Shakespeare defended his decision to field a strong side against Palace despite Tuesday's Champions League quarter-final second leg against Atletico Madrid.
Morgan has 27 appearances under his belt in the Premier League this season and a further eight outings in City's run to the last eight of the Champions League.
"I need to see if there's any reaction from today (Monday's training session)", Shakespeare told reporters. "Where this club has come from has been remarkable".
"It's a great point for us", said Allardyce.
"I'm assured it was just cramp", said Shakespeare.
Cape Town - Atletico Madrid defender Diego Godin believes Leicester forward Jamie Vardy has what it takes to play for most clubs in the world, including Diego Simeone's side.
"You have to have that fire in your belly, but you also have to have cool, smart heads at times".
"We're a bit gutted with the result in the end - if we'd held on to the two-goal lead for a bit longer, we'd have been fine", he said.
"We need to deny them space because they're a very, very good counter-attacking team".
The Leicester skipper has missed the last six games with a back injury.
Leicester appeared set to head into the Atletico match on the back of a victory that would have drawn a line under any lingering relegation fears.
The Premier League champions are 1-0 down from the first leg and will be without Morgan's regular centre-back partner Robert Huth through suspension.
Back in August, when Crystal Palace were managed by Alan Pardew and Leicester City by Claudio Ranieri, Shakespeare took up a part-time position on Allardyce's coaching staff with the England national team.
Leicester overcame a one-goal deficit to defeat Sevilla in the previous round, although on that occasion they went into the home leg with an away goal under their belts.
This game will mean a lot to the Eagles since a victory will all but secure their spot in the Premier League next season so I am expecting them to put out an incredible performance.
"I don't think anybody wants to come here". We both work hard.
"The 10 days at St George's and the game will live with me forever". It was a tremendous fightback from the players and that would not have happened when I first arrived. "It will be decided on the smallest of details".
Benalouane was in the Foxes team eliminated by Atletico Madrid this week.
Leicester lost at the Vicente Calderon last week after referee Jonas Eriksson awarded a penalty after Griezmann was fouled by Albrighton outside of the area.
Koke, Saul Niguez, Gabi and star man Griezmann are all due to return to the starting XI after being completely rested for Saturday's 3-0 home win over Osasuna, which left them third in La Liga.