Moving to bolster the offerings at the 242 ambulatory surgery centers it already operates, Amsurg Corp. has agreed to acquire outsourced physician-services provider Sheridan Healthcare from private equity firm Hellman & Friedman in a transaction valued at $2.35 billion.

The terms of the cash-and-stock deal, which was announced Wednesday, call for Nashville-based Amsurg to fund the purchase via financing provided by Citigroup and by issuing up to roughly $615 million in Amsurg equity to Sheridan Healthcare’s equity holders. Amsurg also has the option to replace a “substantial portion” of the equity consideration with cash.

The acquisition is expected to close in the third quarter of 2014, the two companies announced in a joint statement.

Sunrise, Fla.-based Sheridan, which Hellman & Friedman acquired in 2007, provides outsourced physician services, such as anesthesiology and radiology, to hospitals and ambulatory surgery centers. By acquiring the company, Amsurg expects to expand the types and quality of services it already provides while deepening its relationships with doctors.

“We believe this represents a compelling opportunity to drive growth in our existing markets and to create an even more robust development pipeline across all service lines,” Amsurg president and CEO Christopher Holden said in a statement. “The attractive economic fundamentals support a strong financial profile that will allow the combined company to continue to invest in new growth following completion of the transaction.”

The acquisition is also expected to give Sheridan and its 2,400 health care professionals access to more markets and health systems. Once complete, the deal will allow Sheridan, which currently operates in 25 states, to extend its reach into an additional 13 states.

For legal counsel on the transaction, Amsurg has turned to Nashville-based Bass, Berry & Sims. The firm has served as the company’s primary outside counsel on various matters for more than a decade.

Bass Berry health care and M&A partner Jim Jenkins is leading the firm’s team on the matter. The other Bass Berry attorneys playing a role in the deal are executive compensation and employee benefits partner Curtis Fisher, health care partner Mary Beth Fortugno, labor and employment partner Tim Garrett, corporate partner George Masterson, corporate and M&A partner Andy McQueen, tax partner Bryan Metcalf, real estate partner John Seehorn, real estate partner David Smith, health care partner Danielle Sloane, real estate partner Jim Tate, M&A partner Steve Taylor and health care partner Elizabeth Warren. The associates from the firm working on the matter are Sam Beutler, Stephanie Carter, Meredith Collins, Brad Hart, Che Mock, Mary Leigh Pirtle, Frank Pellegrino, Amy Poe and Amy Sanders.

For its part, Sheridan has turned to Simpson, Thacher & Bartlett as its lead outside counsel on the transaction. The firm has advised Sheridan on corporate matters for seven years and has long represented Hellman & Friedman. Most recently, Simpson was the private equity firm’s counsel on its $1.8 billion acquisition of Applied Systems Inc., which closed in January, and a $2.4 billion disposition of Sedgwick Claims Management Services Inc. to global investment firm Kohlberg Kravis Roberts & Co. in February.

The Simpson attorneys representing Sheridan in this instance include M&A partners Atif Azher and Chad Skinner, capital markets partner William Brentani, credit partner Brian Steinhardt, tax partner Katharine Moir, executive compensation and employee benefits partner David Rubinsky, intellectual property counsel Joshua Walker and environmental senior counsel Michael Isby. The Simpson associates working on the matter are Dena Acevedo, Linda Barrett, Fred De Albuquerque, Dan Kay, Michelle Morad, Linda Nyberg, Alexis Orenstein, David Ray, Karen Reyes Eric Wolf and Judy Yan.

Gibson, Dunn, and Crutcher is representing Citibank in connection with its role as Amsurg’s financial adviser. The team Gibson Dunn team includes New York corporate partners Barbara Becker and Brian Gingold, as well as corporate associate Emily Throop. Becker is the cochair of Gibson’s M&A practice.

Sheridan received financial advice from Barclays, Credit Suisse and Goldman, Sachs & Co. Information about the firms providing legal counsel to those institutions was not immediately available.