By Ray Flowers
July 10, 2008 9:01am CDT

Many times when trying to determine a pitcher's success, we find ourselves gravitating towards ERA, as it is one of the oldest and most well established tool to measure a pitcher's success. Alas, the years have not been kind to ERA, as there are now a myriad of measurements that clearly are better at showing how successful a pitcher has been with things like K/9, BB/9, K/BB and BABIP jumping to the forefront.

For a relief pitcher, ERA is even worse as a measurement of a hurler's success than it is for a starting pitcher. Take the case of Jonathan Broxton, who owns a 3.62 ERA in 37.1 IP. If you remove the one outing where he was apparently telling the batters what he was throwing, his ERA would be 2.17 (the Astros scored six runs off him on May 11th). Therefore, if you looked only at the ERA column on his bubble gum card, you would be mistaken when trying to estimate his effectiveness.

However, this will not be a discussion centering on the relative validity of ERA, rather, we will be looking at another measurement that is more germane to a relief pitchers success, or lack thereof. What is that measurement that I speak of? How about Left On Base Percentage, or the percentage of runners on base who are left stranded without scoring (LOB%).

PART I will discuss American League Relievers.

PART II will discuss National League Relievers.

***Note: The major league average for LOB% is usually right around 70%.

AMERICAN LEAGUE
Minimum 20 IP

LOB%	Last	First
97.2	Nathan	Joe
95.1	Soria	Joakim
95.1	Farnsworth	Kyle
93.4	Morrow	Brandon
92.1	Carlson	Jesse
91.3	Rivera	Mariano
89.8	Downs	Scott
88.2	Casilla	Santiago
88.2	Arredondo	Jose
87.2	Veras	Jose
86.5	Logan	Boone
86.5	Walker	Jamie
86.2	Okajima	Hideki
85.7	Linebrink	Scott
85.0	Wheeler	Dan
84.9	Rodriguez	Francisco
84.1	Lopez	Javier
83.9	German	Franklyn
83.8	Jenks	Bobby
83.8	Cormier	Lance

The runaway leader is Joe Nathan of the Twins at over 97%. Of course, we are just discussing the raw data here in terms of percentages and giving no deference to the actual number of runners stranded. Want an example? Let's say Picher A strands 10 of 10 runners, a 100% strand rate. Obviously that would be better than Pitcher B, who stranded 29 of 30 runners (96.7%), though it could easily be argued that Pitcher B would be the more valuable reliever because of the amount of success that he recorded. So just keep in mind moving forward that we are only discussing actual percentages in this discussion without considering the amount of actual runners that are left on base.

Some others worth mentioning would include the following.

Joakim Soria (95.1%) - He has been just about as good as any pitcher in baseball this season, so it's no surprise to also see him on this list, as well. Soria owns a 0.75 WHIP and a killer 4.89 K/BB ratio, and it's clear he has his teammates' back, as well, when called upon to put out the fire.

Kyle Farnsworth (95.1%) - Maybe the Yankees knew what they were doing when they placed Joba Chamberlain in the rotation after all. Farnsworth is a maddening mix of top shelf talent that often gets lost in his antics (he never met a scrum he didn't want to join) and his seeming propensity to always walk batters at the absolute worst times. This year, though, he has reigned in that tendency, as he has been one of the best in the junior circuit at stranding runners on base.

Brandon Morrow (93.4%) - Has there been a more dominant reliever in all of baseball this year? Perhaps, but there hasn't been another hurler more on his game of late than Morrow, who has allowed all of two hits and one walk over his last 16 appearances spanning 16.2 IP. That's right folks, his WHIP since May 27th is 0.18. That's just sick. When J.J. Putz returns after the break, it is far from certain that he will quickly move back into the closer's role.

Jose Arredondo (88.2%) - Has K-Rod been the most dominating reliever in the Angels pen? Well, there are a whole bunch of measurements that say the answer to that question is no. Arredondo has a better LOB% (88.2 to 84.9), a better K/9 (8.55 to 8.45) a better K/BB ratio (6.33 to 1.63) and a better WHIP (0.75 to 1.17). If K-Rod were to go down with an injury, it could be Arredondo, and not Scot Shields, who picks up the ninth inning duties.

B.J. Ryan (82.9%) - Has made a remarkable recovery from Tommy John surgery, performing as well as could have been hoped after throwing only 4.1 innings last season. His digits on the year: 16 saves, a 1.27 WHIP and a 9.3 K/9 mark. However, lost amidst the hoopla with Ryan has been the excellent work of setup man Scott Downs (89.8%), who, much like Arredondo in Anaheim, has been arguably a better pitcher than his team's closer. From May 1st through June 29th, a span of 25 appearances covering 26 IP, Downs didn't give up a single run.

Rafael Perez (81.2%) - The Indians finally made the move that we could all see coming since early in spring, and that was removing Joe Borowski from the closer's role. The question now becomes who will take over at the end of the game? Most pundits seemingly favor Masa Kobayashi (77.3%) for the moment, especially after Rafael Betancourt (66.4%) failed for about the 9th time to take over the closer's role when given the chance. However, the best pitcher under consideration for the role in terms of stranding runners is lefty Rafael Perez, though he has struggled with his overall production of late (4.38 ERA, 1.62 WHIP, 4.38 BB/9 since May 1st).

George Sherrill (80.0%) - Sherrill has been tremendous this season with the second-most saves in baseball (27, tied with Jonathan Papelbon). However, would it surprise you to learn that Jamie Walker (86.5%) and Lance Cormier (83.8%) both have a better LOB%? Jim Johnson (78.4%) also isn't that far behind, either, so with those four hurlers the Orioles pitchers have to feel pretty good when the manager comes to take the ball, that whomever is called on will do a great job in limiting runners from scoring.

Huston Street (76.7%) - He continues to strike out more than a batter per inning (42 in 38 IP), while limiting base runners effectively (1.05 WHIP). He hasn't been great at stranding runners, but he has been solid as he almost always is, though his BB/9 rate of 2.60 is quite a bit above the 1.86 mark he posted in 2006-07.

Octavio Dotel (72.9%) - With Bobby Jenks (83.8) out of action due to some lingering soreness in his non-throwing shoulder (he expects to return right after the All-Star game), the White Sox will have a couple of options that are having solid years to turn to late in games. Scott Linebrink (86.2%) was off to the best start of his career until hitting the dumps of late by allowing runs in four straight appearances (five runs in four IP leading to two blown saves). Dotel, on the other hand, has been unbelievably dominating with 57 K in 41 IP, good for a 12.51 K/9 mark. However, his LOB% is just barely above the big league average, so perhaps he should just avoid putting runners on base.

Jonathan Papelbon (66.0%) - Always in the discussion of best closers in baseball, Papelbon has been awful this year at stranding runners on base. The good news is that Papelbon doesn't allow many runners to reach base with a 0.91 WHIP, but over his last 7.1 innings he has allowed three runs to leave him with 10 earned runs on the season, just two fewer than he gave up last season, though he has thrown 18.2 fewer innings this year.