Mesirow Financial Chief Executive James Tyree, who has been battling cancer, was recently hospitalized with pneumonia.

“They are treating his infection and he’s feeling stronger every day,” Mesirow President Richard Price said in an e-mail to workers Tuesday. “Doctors generally expect some side-effects and complications during an aggressive chemotherapy regimen.”

Tyree, who also heads Sun Times Media, had suffered from diabetes for years and had a transplant operation a few years ago.

“I’ve assured him that the business is fine, and we are following our plan,” wrote Price, who has been overseeing day-to-day operations.

He said Tyree “was pleased to hear that the budget process went well and was nearly complete.”

Doctors aren’t sure how long he’ll be hospitalized.

“During his absence, it’s business as usual,” Price told Mesirow workers. “I’ll keep Jim updated, and he can work remotely when he’s feeling better.”