Braves relief pitcher Jonny Venters will not throw at all for a period of four weeks after getting a platelet-rich plasma injection in his sore left elbow Tuesday.

Diagnosed with a sprain after leaving a spring-training game one week ago, Venters was given the injection by Dr. James Andrews a day after Andrews examined him in Pensacola, Fla. He will be shut down for four weeks, after which he’ll begin a throwing program.

The hope is that Venters has only inflammation associated with a sprain, rather than more serious ligament damage, and that the PRP treatment and rest will allow him to begin throwing again in a month.

Andrews performed Tommy John elbow surgery to repair Venters’ torn ulnar collateral ligament after the 2005 minor league season. An MRI exam of the elbow this week was inconclusive, which Wren said often is the case in patients who had previous Tommy John surgery.

Braves general manager Frank Wren said there is no timetable for Venters’ possible return from the 15-day disabled list. The Braves will wait to see how he recovers and how he feels after he resumes throwing.

“We’re just optimistic that the four weeks will get it calmed down and get him back throwing,” Wren said.

While the MRI didn’t rule out ligament damage, Wren said Andrews did other tests that made the doctor optimistic and led to the recommendation of the PRP injection and rest.

PRP is an emerging form of treatment to stimulate the healing of soft tissue without resorting to surgery and a longer recovery. Braves pitcher Kris Medlen got a PRP injection during his rehabilitation from Tommy John surgery after scar tissue tore during the healing process.

Chad Billingsley and Zack Greinke of the Dodgers are among the others who’ve recently had PRP injections in their pitching elbows, Billingsley in August 2012 for a partial ligament tear and Greinke last month for inflammation. Golfer Tiger Woods had the treatment for a knee injury several years ago.

Venters has been a key part of a bullpen rated among baseball’s best. The 28-year-old lefty had 230 appearances in his first three major league seasons through 2012, including a majors-leading 85 in 2011, when he had a 1.84 ERA and limited hitters to a .176 batting average.

The Braves are better prepared than most teams to replace a relief pitcher. They already had two other left-handed relievers, standout veteran Eric O’Flaherty and impressive second-year man Luis Avilan. They acquired another setup man, former Angels closer Jordan Walden, in an offseason trade for Tommy Hanson.

“This is precisely why we felt we needed to go out and get another power arm,” said Wren, referring to the precarious nature of pitching and the need for depth. “You can’t assume health, and you don’t want to get caught short.”

Since the beginning of the 2010 season, Sean Marshall (231) is the only major league pitcher with more appearances than Venters.

He had a career-high 3.22 ERA in 66 appearances last season, but Venters pitched much better after returning from a July stint on the disabled list for elbow inflammation.

After posting a 1.80 ERA in his first 173 career appearances through April 30 of last season, he had a 6.08 ERA in 31 appearances from May 1 through July 4. Returning from the DL on July 22, he had a 1.71 ERA in his last 26 appearances.