The “immaculate inning” is a rare feat in baseball.

That is, a pitcher recording three straight strikeouts on the minimum number of pitches, or nine.

Boston’s Rick Porcello, the reigning American League Cy Young Award winner, tossed the eighth such immaculate inning this season, a new MLB record. The previous high was seven in 2014.

Porcello’s work of efficiency was the second by a Red Sox pitcher this season, with reliever Craig Kimbrel turning the trick during a game in May. Porcello’s feat was also just the fourth immaculate inning in Red Sox history.

With pitchers being severely limited in pitch count, tossing a nine-pitch inning is a boon to efficiency. But, with batters bigger, better and generally smarter these days, strikeouts and low pitch counts are at a premium. Put it this way, no one will ever come close to Nolan Ryan’s 383 K count in 1973 (which was eighth all-time and long after previous records set in the 1800s).

With that in mind, we give you the most efficient strikeout pitchers in baseball today, with more of a focus on strikeouts per nine innings, average than just total strikeouts.

15. Michael Pineda – New York Yankees

The Yankees will probably miss Michael Pineda during this stretch drive. The four-year Yanks’ veteran starter was put on the 60-Day DL recently and will require Tommy John surgery. In parts of four years in the Bronx, Pineda could be counted on to take the ball every fifth day and over the course of his time in pinstripes he got better at setting down hitters via the K. Pineda started his career with Seattle in 2011 and was an All-Star, before undergoing surgery in 2012 and missing most of that season and the 2013 campaign as well. In 2014, he was 5-5 in 13 starts for the Bombers and recorded 56 strikeouts in 76.1 innings, or 7.0 SO/9. He increased that to 8.7 in 2015 and then in 2016, despite a losing record (6-12) and so-so ERA (4.82), he led the American League in strikeouts per nine at 10.6, or 207 total in 175.2 innings. His lifetime mark is 9.1.

(AP Photo/Jae C. Hong)

14. David Price – Boston Red Sox

Just like the Yankees, who are in tough for a playoff spot, the AL East leading Boston Red Sox are probably hoping David Price draws back into the line-up sooner, than later. Price struggled somewhat this year, going 5-3 in 11 starts with a 3.82 ERA, but he is still one of the better strikeout pitchers in the game. He logged 8.6 SO/9 before going put on the 10-day DL on July 28, with 63 Ks in 66 innings. In just about every year since 2011 Price has been in the top 20 in strikeout efficiency, finishing as high as sixth in 2014 with 9.8 SO/9. He led the American League in strikeouts that season, with 271 in a league high 248.1 innings pitched. Lifetime, Price has recorded 8.6 strikeouts per nine innings in 264 games.

(AP Photo/Michael Dwyer)

13. Noah Syndergaard – New York Mets

Just how good would Noah Syndergaard look in a Toronto Blue Jays uniform? The Jays dealt Syndergaard, one of their top 3 prospects in 2015, to the Mets in a deal that brought in R.A. Dickey that year. With all the troubles with starting pitching the Jays have had and may be looking at in the near future, trading him away may have been a big mistake. Now, Syndergaard is on the long-term disabled list this season with a torn lat muscle in his pitching arm and has started in just five games thus far. In his limited time in the Mets rotation since 2015, Syndergaard has been among the league leaders in SO/9, clipping along at 10.4 average. Last year, his best so far, Thor racked up 218 strikeouts in 183.2 innings, finishing fourth in that category at 10.8 SO/9.

(AP Photo/Julie Jacobson, File)

12. Chris Archer – Tampa Bay Rays

The Rays are fighting it out for a wild card spot this season, due in no small part to the efforts of staff ace Archer. In May alone, Archer set a franchise record with strikeouts in a month at a whopping 58. As of Thursday, he is fifth in the major leagues in strikeout efficiency, logging a personal best 11 per nine, or 189 in just 154 innings. His record is 8-6 in 24 starts, a far cry from a hard luck 2016, when he had the most losses in the American League and was 9-19. Even though it looked as if he pitched poorly, Archer tossed 233 Ks in 201.1 innings, his second straight season with 200+ innings of work. A look at his last three seasons shows how consistent he has been at setting down batters with a whiff, with 674 strikeouts in 567.1 innings.

(AP Photo/Gene J. Puskar)

11. Robbie Ray – Arizona Diamondbacks

Just like Chris Archer in Tampa, young D-Backs starter Robbie Ray is rounding into form after a couple of so-so seasons. And the Snakes, like the Rays, are also battling for a wild card spot and will rely on big arms like Ray’s to get them there. Right now, though, he is on the 10-day DL after suffering a concussion in a game on July 28. Prior to that, the four-year veteran logged a 9-5 record, 3.11 ERA and 151 Ks in 118.12 innings. The first time All-Star is currently fourth in strikeout efficiency with 11.5 SO/9, a year after posting a 11.5 average, which was second only to the late Jose Fernandez in 2016. The bearded lefty has transitioned from being a decent power pitcher in the minors (8.9 SO/9 in six seasons) to a more robust strikeout man in the majors (10.2 SO/9).

(AP Photo/Ross D. Franklin)

10. Jacob deGrom – New York Mets

In the absence of Noah Syndergaard, fourth-year starter Jacob deGrom has assumed the mantle of New York Mets starting rotation ace. He has been fairly superb this season, recording a 12-5 won-loss mark, along with a 3.38 ERA and 170 strikeouts in 144.2 innings of work, which works out to 10.6 SO/9, seventh best in the bigs. The lanky righthander has been as consistent a starter as the Mets could hope for since being NL Rookie of the Year in 2014. His stuff has gotten better year over year and 2017 could turn out to be his best yet. Eight times he has thrown for double digit strikeouts, his best overall effort being a three-hit, one earned run and 12 strikeout effort in a 2-1 victory over Philadelphia on June 30.

(AP Photo/Gregory Bull)

9. Gio Gonzalez – Washington Nationals

Never anyone’s pick for top starter on the Washington Nationals, Gio Gonzalez has nevertheless been a model of absolute consistency since 2010. He was an All-Star in 2011 with Oakland and again in 2012 with the Nats, when he was 21-8 with a 2.89 ERA and a NL leading SO/9 of 9.4 (207 strikeouts in 199.1 innings). In his last eight seasons, six with Washington, Gonzalez hasn’t failed to record double digit wins (he is 10-5 this season, so far) and never had a losing season. His ERA has been as low as 2.59 this season and as high as 4.57 in 2016, and is usually between 3.00 and 4.00. As for his overall strikeouts per nine innings in that span, the southpaw has averaged around 8.8. Good stuff and a big component of a first-place squad.

(AP Photo/John Minchillo)

8. Justin Verlander – Detroit Tigers

Despite not being traded at the deadline this year, Justin Verlander is still a wanted man in just about every contending team’s starting rotation. And after a sparkling one-hit, eight inning performance in a 10-0 victory over Pittsburgh Wednesday night, he will be a topic of hyperbolic water cooler trade talk in the coming days. It hasn’t been the best of seasons for the Tigers long-time ace, but even still, he is 8-7 in 24 starts, with 142 Ks in 145 innings (8.8 SO/9). Over the course of his 13-year career, the power pitcher and workhorse has been among the league leaders in strikeouts (leading the American League four times) and efficiency (league high 10.1 in 2009). The six-time All-Star, and 2011 AL Cy Young and MVP award winner has a career SO/9 of 8.5 (2,339 Ks in 2,484 innings pitched).

(AP Photo/Paul Sancya)

7. Yu Darvish – Los Angeles Dodgers

If his first start with his new team, the Los Angeles Dodgers, is any indication of what he could mean to a potential World Series championship, Yu Darvish announced himself loudly. The four-time All-Star with Texas got a new lease on life, being dealt to the Dodgers at the deadline and on Aug. 4 he went seven innings in a 6-0 victory over the Mets, giving up just three hits and striking out 10 (which was the fifth such 10 or more strikeout performance of his season). In his stellar five-year career, Darvish has been among the most efficient strikeout hurlers, recording strikeouts at a rate of 11.1 per nine innings, in 123 total starts. He finished second in AL Cy Young voting in 2013, when he was tops in the loop with 277 Ks in just 209.2 IP, easily leading all major league pitchers in efficiency at 11.9 SO/9. Look out, National League.

(AP Photo/John Amis)

6. Zack Greinke – Arizona Diamondbacks

A young hurler like Robbie Ray sure has a good mentor in long-serving vet Zack Greinke. After a so-so 2016 campaign, Greinke is back in form this year, going to the All-Star game for the fourth time and recording a 13-5 record and 165 strikeouts in 149 innings. Looking over his great career, a 10.0 SO/9 average might not seem like much, but consider that at 33 he has far surpassed his previous five seasons in that category. He last logged over 10.0 SO/9 in 2011 with Milwaukee, when he best in the majors at 10.5 (201 strikeouts in 171.2 IP). Greinke has never had really high strikeout totals, but makes the most of his command to limit homers (0.9 per nine innings, lifetime) and walks (2.2 per nine innings). A great one on a Diamondbacks team going somewhere this season.

(AP Photo/Nam Y. Huh)

5. Stephen Strasburg – Washington Nationals

Life is good in D.C. these days. The NL East leading Nationals have a commanding 14-game lead (as of Thursday) and an embarrassment of riches in their starting rotation. Along with Max Scherzer, Gio Gonzalez and Tanner Roark, Stephen Strasburg helps form one of the most formidable starting four in major league baseball. Washington’s first overall pick in 2009 is currently shelved with elbow inflammation and was 10-3 with a 3.25 ERA and 141 strikeouts in 121.2 innings this season (10.4 SO/9). The three-time All-Star is the active leader among all major leaguers, career, with 10.5 K/9, which is impressive in itself considering how closely his pitches per start have been monitored and limited. The big righty has thrown a simulation game recently and is eyeing a return soon, which can only be a good thing for the front-running Nats.

(AP Photo/Carolyn Kaster)

4. Corey Kluber – Cleveland Indians

There is a theme here and it runs to the fact that good teams have great pitching. At this point in the 2017 season, the surging Cleveland Indians are riding the arm of 2014 Cy Young award winner Corey Kluber, who is second in the majors only to Chris Sale in strikeout efficiency at a career high 12.4 Ks per nine innings. Put it this way, he had a fine season in 2016, winning 18 games like he did in his Cy Young year and tossing 227 strikeouts in 215 innings for an average of 9.5 per nine. This year, he already has 183 Ks, in just 132.2 innings of work. And, the two-time All-Star is just getting better with every start, post All-Star break. He set a record for most consecutive starts with 10 or more strikeouts after the mid-Summer Classic, with five. The Tribe is in first place in the AL Central, which should make everyone else in the league just a tad nervous.

(AP Photo/Tony Dejak)

3. Clayton Kershaw – Los Angeles Dodgers

Just think how devastating Dodgers pitching will be down the stretch when Clayton Kershaw returns to the line-up after rehabbing his back injury. L.A. owns the best record in baseball (80-33) and holds a whopping 15.5-game lead on two very good teams behind them, Arizona and Colorado. Before he went on the disabled list on July 23, Kershaw was easily the leader of the pack for a fourth NL Cy Young award. He is 15-2 in 21 starts with a league leading 2.04 ERA and 168 strikeouts in 141.1 innings (10.7 SO/9). He has twice led the senior circuit in that stat, back-to-back in 2014 (his last Cy Young year) and 2015. He has achieved his great 9.9 career K/9 mark not by being a smashmouth power pitcher, but a guy who mixes velocity and pitch variation to keep hitters way, way off balance. The Dodgers are scary, and about to become a lot spookier when Kershaw draws back in.

(AP Photo/Charles Rex Arbogast)

2. Max Scherzer – Washington Nationals

A Nationals/Dodgers NLCS would be a screamer, if it comes to fruition this season. With arguably the two best staffs in baseball, these two squads would stage an epic seven-game series. Adding his name to a potent mix of Cy Young candidates this year is reigning NL Cy Young winner Max Scherzer, who also won one with Detroit in 2013. Scherzer was lights out in 2016, going 20-7 with a 2.96 ERA and a league leading 284 strikeouts in 228.1 innings (11.2 SO/9). He may not be on pace for 20 wins this year at 12-5 through 23 starts, but he is again leading the NL in strikeouts (210) and innings pitched (153.1) and his 12.3 SO/9 is third overall in baseball. Lifetime, Scherzer has recorded 2,091 strikeouts in 1,849.2 innings pitched, for an average of 10.1, which is third among all active pitchers.

(AP Photo/Mark Tenally)

1. Chris Sale – Boston Red Sox

The Bosox better hope Sale stays healthy. They hold a slim four-game lead in the AL East over the Yankees in a tough, tough division where anything can happen in August and September. But, the front-running Cy Young candidate is quite healthy right now and mowing down the competition at a frightening clip. He leads the American League in wins with 14 (14-4), ERA (2.57), innings pitched (161.1), strikeouts (229) and SO/9 (12.8, best in baseball). The hard-throwing southpaw is, in our estimation, the most efficient and devastating strikeout pitcher in baseball and he’s just getting going at 28. A six-time All-Star and perennial top-5 Cy Young candidate, Sale looks like he is on a mission this season, also leading the AL in hits/nine innings at 6.3 and WHIP at a miniscule 0.880.

(AP Photo/Charles Krupa)