LOUISVILLE, Ky. – Humana, Inc., announced today that it has reached a definitive agreement to sell Concentra, Inc., for $1.05 billion in a cash transaction.

Concentra is being acquired by MJ Acquisition Corp., a joint venture between Select Medical, a leading operator of specialty hospitals and outpatient rehabilitation clinics in the U.S., and Welsh, Carson, Anderson & Stowe, a private equity fund. The sale is expected to close later this quarter, subject to customary adjustments, according to a Humana press release.

A leading insurance and managed cared company, Humana acquired Concentra – one of nation’s largest providers of occupational health, urgent care and physical therapy services – in December 2010 for $790 million. Concentra traces its roots to OccuSystems, a clinic network founded in Texas by Richard Rehm, M.D., in 1979.

The Concentra acquisition was envisioned as a way to offer Humana health plan members access to conveniently located clinics. Humana’s expansion efforts also include investments in primary care platforms such as owned physician practices and medical services organizations (MSOs). As the company’s strategy has been refined in recent years, the primary care platform has proven to better advance the company’s integrated care delivery model than Concentra’s focus on occupational injuries, Humana officials said.

“We greatly appreciate the focus on consumers and quality of health care our Concentra associates demonstrate on a daily basis,” said Bruce D. Broussard, president and CEO of Humana. “Though Concentra’s operations did not ultimately align with Humana’s strategy as well as we had originally anticipated, we believe Humana and Concentra have gained valuable insights into consumer behavior over the past several years that will serve us both well moving forward. We expect Humana will continue to invest in other primary care assets, including MSOs, as we continue to expand our integrated care delivery model.”

The acquisition expands Select Medical’s outpatient segment by about 300 clinics. It’s familiar territory for Welsh Carson, which previously owned both Concentra and Select Medical.