On Assignment Inc. announced Tuesday that it will sell its physician staffing segment, Vista Staffing Solutions Inc., for $123 million.

The Calabasas staffing company expects the transaction will happen in February, with net proceeds between $102 million and $105 million. Vista had 2014 revenue of about $135 million.

The buyer is Envision Healthcare, a firm specialized in providing ambulance and emergency room personnel with headquarters in Greenwood Village, Colo.

Peter Dameris, chief executive of On Assignment, said Envision approached him about a deal and it became apparent the sale would benefit both companies.

“This transaction will provide us with additional cash to pursue strategic acquisitions, execute repurchases of shares, increase investments in our organic growth strategy and pay down debt,” he said in a statement.

Shares closed up $1.59 or 4.9 percent to $34.02 on the New York Stock Exchange.