One lefty reliever has already been traded this month, with Matt Thornton going to the Red Sox in exchange for outfield prospect Brandon Jacobs. Over the past couple of years, lefties Randy Choate, Craig Breslow, Marc Rzepczynski and Trever Miller have been involved in July swaps as well. The Braves are reportedly one team in the market for left-handed relief help, but they'll be far from the only ones searching.
Here's a look at some of the names who could be on the market and the roles in which they've been used (though admittedly not all fall neatly into one category)…
Glen Perkins (Twins)
The Twins are just one of two teams to regularly deploy a left-handed closer, and the other (Cincinnati's Aroldis Chapman) isn't even up for debate. GM Terry Ryan has turned away early inquiries on Perkins, which is understandable. Perkins is in the first year of a three-year, $10.3MM contract that contains a $4.5MM club option. He's pitched to a 1.82 ERA with 12.2 K/9 and 1.8 BB/9 in 2013, and he has a 2.38 ERA dating back to 2011. On top of that, the Minnesota native is beloved by his hometown fans. Interested parties would likely have to make a shockingly large offer to acquire the 30-year-old.
Oliver Perez (Mariners), Mike Dunn (Marlins), Scott Downs (Angels), Antonio Bastardo (Phillies), Mike Gonzalez (Brewers), James Russell (Cubs), Darren Oliver (Blue Jays)
Perez has risen from the ashes to rebuild his career as a successful late-inning reliever. After a disastrous three-year deal as a starter with the Mets, he returned to the Majors in Seattle's bullpen last season. In 65 2/3 innings from 2012-13, Perez has posted a 1.92 ERA with 10.1 K/9 and 3.4 BB/9. He's been terrific against both lefties and righties, and he earns just $1.5MM this season before hitting the open market.
The Marlins have flatly said that they don't want to trade Dunn, but some of that could be posturing, and teams will still surely be checking in. Like Perez, he's been effective against righties as well as lefties this season, holding each to an OPS under .670. His command is improved from 2012, though it's still shaky (4.4 BB/9), and he also whiffs about a batter per inning. Dunn is controlled through 2016, so an acquiring team would have to pay for three and a half years of his service.
Downs has obliterated opposing left-handers (.444 OPS) and held his own against right-handed hitters (.706 OPS). In the final season of a three-year, $15MM pact with the Angels, he is set to hit free agency at season's end. He's been one of the game's most effective lefty setup men since 2007 and has a bit of ninth-inning experience as well (25 saves in that time).
Bastardo's excellent strikeout rate has dipped a bit in 2013, but he's still whiffed more hitters than innings pitched with his typical rocky control. He's been effective against right- and left-handed hitters throughout his career, and he's earning just $1.4MM this season as a first-time arbitration player. The Phillies aren't clear sellers, but if they decide to move some pieces, Bastardo will be of interest.
Gonzalez is used primarily against left-handed hitters, though he hasn't been outstanding against righties or lefties. He's a free agent at season's end and earning just $2.25MM, however, which seems like a perfectly reasonable price for a 3.00 ERA, 10.9 K/9 and 4.6 BB/9. Both FIP and xFIP suggest that his ERA should be about a full run higher, however. The Brewers' pen has drawn quite a bit of interest thus far.
Russell's stock has fallen after he posted a 5.56 ERA in 11 1/3 innings in June. Forced to face more right-handed batters due to deficiencies in the Cubs' bullpen, he was hit hard and saw his sub-1.00 ERA soar. However, he's still at 2.78 on the season and has seven straight scoreless appearances (though he's totaled just 3 1/3 innings in that stretch). Russell is controlled through 2015, but his career splits suggest that he's more of a lefty specialist than a true setup man.
Oliver, strangely, has been hammered by lefties this season but dominated right-handed hitters. The seemingly ageless 42-year-old is a free agent at season's end but could be a big boost to a contender's relief corps if he can rediscover his typical form against lefties.
Multiple Inning Relievers
Tom Gorzelanny (Brewers), Brian Duensing (Twins), Charlie Furbush (Mariners), Brett Cecil (Blue Jays)
Gorzelanny has a long background as a starting pitcher, but he's been used primarily in relief for the Brewers. His final two appearances prior to the All-Star break were starts, however, and that flexibility is likely appealing to other clubs. He's more effective against left-handers but has gone multiple innings numerous times this season. He can be controlled via arbitration for the 2014 season.
Duensing has been jerked back and forth between the Twins' rotation and bullpen throughout his career, but his glaring platoon splits indicate that he's best suited for a role as a left-handed specialist. He's been unusually susceptible to left-handed opponents this season but has held them to a .583 OPS for his career (compared to .828 for right-handed hitters). The former third-round pick is under team control through 2015.
Furbush isn't a free agent until after the 2017 season, so there's no rush for the Mariners to trade him. He's been reasonably effective against righties and stifled lefties, and he's thrown more than one inning in 10 of his appearances so far this season. Teams in need of relief help would undoubtedly be happy to land a lefty of that ilk.
Cecil is holding righties in check for the first time this season and has worked an inning-plus multiple times as a result. Lefties have a sub-.400 OPS against him, and he's under control through 2016 as a Super Two player. The first-time All-Star would likely have a notable asking price.
Javier Lopez (Giants), Joe Thatcher (Padres), Travis Blackley (Astros), Wesley Wright (Astros)
Wright has been hit by both lefties and righties this season but excelled against lefty swingers in 2012. He can be controlled through 2015 and is making just $1.03MM after going through arbitration for the first time this past offseason.
Lopez, Thatcher and Blackley have been used primarily for one or two outs recently, and all three have held left-handers to an OPS under .600, with Thatcher limiting them to a brilliant .458 mark. Lopez is a free agent following the season, while Thatcher is controlled through 2014 and Blackley can be controlled through 2016. Blackley has starting experience as 2012 with the A's, so he could theoretically be stretched out into a longer role, though his splits aren't encouraging.
For more on the 2013 trade market, take a look at Tim Dierkes' examination of the market for catchers, first basemen, shortstops, third basemen, starting pitchers and designated hitters as well as my own look at the market for second basemen, corner outfielders, center fielders and right-handed relievers.