The Cardinals have endured their share of bullpen woes this season, with closer Trevor Rosenthal’s demotion and control problems looming large among the team’s relief troubles. St. Louis has also seen Kevin Siegrist diagnosed with mononucleosis, and right-hander Jordan Walden has yet to throw a pitch for the big league club this season. Derrick Goold of the St. Louis Post-Dispatch spoke to general manager John Mozeliak, and Goold writes that while the GM said he has not yet been “knee-deep” in the market for relievers, the Cardinals are indeed surveying the market.

Goold lists D-backs right-hander Brad Ziegler as a potential option for the Cards and also notes that Yankees lefty Andrew Miller has been of interest to the Cardinals in the past, though demand for Miller would of course be extreme and the asking price figures to be exorbitant. It’s not entirely clear that either will be available, as D-backs GM Dave Stewart has expressed interest in extending Ziegler, while the Yankees haven’t given any indication of selling just yet and control Miller for another two seasons at a reasonable rate.

Mozeliak did voice some confidence that the club would eventually have a healthier Siegrist to help the relief corps, and he acknowledged top prospect Alex Reyes as “the most dynamic thing that we could add to this club with the least acquisition cost, for sure.” Optioning Rosenthal to sort out his control issues isn’t yet on the Cardinals’ radar, per Mozeliak, although as Goold points out the club hasn’t been afraid to take that type of measure with either Kolten Wong or Randal Grichuk this season.

If the Cardinals do ultimately decide that the trade market is the best avenue by which to upgrade its relief contingent, there will be no shortage of options available. A number of the players listed on Jeff Todd’s most recent collection of the league’s top 20 trade candidates are of the relief variety, as are several of the 10 under-the-radar trade candidates he profiled just yesterday. While a number of clubs haven’t yet made a firm determination as to whether they’ll be buyers or sellers on the summer trade market, the Padres and Braves have already sold off big league pieces, while the Twins, Phillies, Brewers, Reds, Athletics and Angels could all follow suit to varying degrees in the weeks leading up to the Aug. 1 non-waiver deadline. The Cardinals don’t always dive headfirst into the trade market with high-profile additions, but the team has a history of adding bullpen pieces as necessary. In recent years, St. Louis has added pieces such as Jonathan Broxton, John Axford and Steve Cishek on the summer trade market.

In light of Rosenthal’s struggles, offseason signee Seung-hwan Oh has been shifted into the closer’s role. They’ve also received quality innings from right-handers Broxton and Matt Bowman as well as lefties Siegrist and Tyler Lyons. Regardless, there’s room for some improvement, as the team’s overall bullpen has a 3.78 ERA that is weighted heavily by Oh’s dominant 1.71 ERA.