Defender Lees is nursing a hip problem and striker Morison has a calf complaint.
Both players had to come off on Tuesday night while a third player, striker Ross McCormack, will also be checked out after suffering a bang on the head during the Championship clash at Elland Road.
All three players are concerns ahead of the visit of West Yorkshire rivals Huddersfield for Saturday's lunchtime kick-off.
"It was like battle stations in the dressing room afterwards," Leeds boss Neil Warnock told the club's official website. "Tom Lees and Steve Morison will both have precautionary scans so we'll see where are with them.
"Ross took a bang and couldn't remember the second half so we'll look at him as well.
"There were a few others who took knocks and bumps as well so we'll have to see where are.
"We'll have a team out on Saturday and be strong, and the lads who play will stand up and not shirk anything."