University officials suspended Leach on Monday while the school investigates complaints from James and his family about how the player was treated.
Defensive coordinator Ruffin McNeill will be the interim coach when Texas Tech plays Michigan State in the Alamo Bowl on Jan. 2.
A person close to James with direct knowledge of the situation contends the player was twice forced to stand in a small, dark place for hours while the team practiced. The person spoke to The Associated Press on the condition on anonymity because of the ongoing investigation.
Liggett said he has a letter from the doctor who examined James that supports Leach's actions.
"He was not hurt by what happened in the equipment room," the lawyer said. "And Mike did not do anything to worsen the situation, in fact he put him in a safer environment by being inside."
Jerry Turner, vice chairman of the university system's board of regents, said the investigation is being handled by the school president's office, with the assistance of its general counsel and athletic director Gerald Myers.
The NCAA is letting Texas Tech conduct its investigation and has not gotten involved, NCAA spokesman Cameron Schuh said. A Big 12 spokesman did not immediately return an e-mail seeking comment.
James was injured Dec. 16 and the next day was diagnosed with a concussion by team doctors, the person close to James said.
According to the person, the player was sequestered at two consecutive practices:
- On Dec. 17, James said Leach told trainers to put him "the darkest place you can find." James was sent to an equipment shed near the practice field, where a member of the athletic staff checked on James to make sure he did not lean against anything or sit on the floor. James said Leach told him that if he came out he would be kicked off the team.
- When the team returned to practice two days later, on Dec. 19, James said Leach told trainers to "find the tightest, darkest place" for the player. James, in his street clothes, was put in an electrical closet inside the football stadium for hours, again monitored by a member of the athletic staff.
Turner declined to comment on whether, if true, the incidents might lead to Leach's departure from Tech.
"We haven't gotten to that point, of course," Turner said. "This is an ongoing inquiry, and I certainly do not want to prejudice the results of the inquiry."
The school was notified of the allegations the evening of Dec. 19, he said, and officials began looking into them the next day.
"This is a personnel matter, and we're very careful with how we discuss those," Turner said.
A blizzard in Lubbock last Wednesday and the Christmas holiday prevented the initial inquiry from being completed before school president Guy Bailey decided to suspend Leach on Monday.
Turner said Bailey conferred with him, fellow regent Larry Anders and Myers.
"It was more of a decision of the president with a sounding board review of the others," Turner said.
He said he did not know "who else needs to be contacted, what other files need to be reviewed" as the inquiry moves forward.
"I really don't know what's next on the agenda," he said.
Tech is the second Big 12 school to launch an internal investigation into a coach's treatment of his players.
On Nov. 16, Kansas investigated Mark Mangino, who was the national coach of the year and got a big raise when he went 12-1 in 2007. Players said he was insensitive, though others defended him.
Mangino resigned Dec. 3 after reaching a settlement with the school that was later disclosed as a $3 million buyout.
James played behind former Texas Tech wide receiver Eric Morris, who defended Leach on Tuesday and said his former coach would never jeopardize the well-being of his players.
Morris, who graduated last year, described the electrical closet inside the stadium as a roomy enough space where the visiting media gathered for interviews after games. Morris said Leach mostly relegated injured players to what the team knew as "Muscle Beach" -- an area beside the practice field where those not healthy enough to play did strength and conditioning work.
Morris said Leach liked to keep injured players close so they could encourage their teammates and not "just be sitting around inside doing nothing."
Liggett said Leach's contract calls for him to receive a $800,000 bonus if he is Texas Tech's coach Friday.
Turner was uncertain whether the suspension meant Leach would not be eligible for the bonus.
Liggett seemed certain.
"It's our position that, of course, he's the head coach, and of course, he's owed the money," he said.