And, not because of Texas Tech.
"I think it has to do more with him wanting a new challenge," said Harrell, who has helped lead the Red Raiders to an 11-1 record this season.
"But if he stays he's going to continue to be successful here, and I'd love to see that."
Texas Tech made its first formal contract offer Friday to Leach's agents -- a five-year deal worth a total of $12.1 million, Texas Tech athletic director Gerald Myers told The Dallas Morning News.
Myers said the last three years of the contract would pay Leach a total of $7 million. The contract is in Leach's agents' hands. They will likely review it this weekend and give Myers an answer early next week. Leach is signed through 2010.
"We made what we think is a good offer," Myers told the Morning News. "It's an offer we feel that's fiscally responsible with all the other obligations in the department. We think it's a good, fair offer. We want Mike to be our coach and hopefully he will accept it."
A source close to Leach told ESPN.com he has not started talks with Texas Tech, but dialogue might begin on Saturday. A source within the athletic department said Leach is planning to stay on as coach of the Red Raiders.
Leach's name reportedly remains on the wish list at Auburn, two days after Tommy Tuberville resigned as coach of the Tigers.
Harrell, whose non-throwing hand was heavily bandaged following his surgery Sunday to repair nine bones broken in his pinkie and ring finger, spoke to The Associated Press about Leach's future Thursday afternoon.
Harrell injured his left hand in Texas Tech's 35-28 win over Baylor on Saturday.
He said Leach "gets more out of less than probably anyone in the country" because he doesn't get first shot at top recruits -- those players usually get calls from Oklahoma and Texas first.
"He deserves every penny he gets, he deserves every offer, and wherever he goes he'll be successful, and it'll be fun to watch," Harrell said.
Information from The Associated Press was used in this report.