Rosenthal deal gives Nats another late-inning power arm

The Nationals, like most clubs, typically take their time in free agency, wait out the market and strike when they have an opportunity to sign a player over the winter. Today, they showed they aren't afraid to dive right in, though, and swoop up an appealing free agent only days after he became eligible to negotiate with teams.

In agreeing to terms with Trevor Rosenthal, the Nats made a rare Halloween transaction to add an experienced and accomplished power arm to the back end of their bullpen, electing not to wait and risk losing out on a player that intrigued them.

Rosenthal's signing, which was confirmed by a source familiar with the deal after it was first reported by USA Today, is still pending a physical. It likely won't become official for several days. But once it does, it will be the first significant move general manager Mike Rizzo has made to fill one of several roster holes that need to be addressed this winter beyond the overriding question of whether to re-sign Bryce Harper or not.

The contract guarantees Rosenthal $7 million, but includes a variety of incentives that could make it worth as much as $28 million over two seasons, according to another source. There is a mutual $7 million option for 2020 that would automatically vest if the right-hander appears in 50 games or finishes 30 games next season, plus more performance bonuses that could add to the overall total value.

The layered structure of the contract is evidence of a lack of certainty about Rosenthal's ability at this point, which is understandable given that he missed the entire season after having Tommy John surgery. The Nationals, though, were willing to take the risk - a relatively minor one, financially speaking - because of the high potential for the reliever to return to elite form.

Rosenthal was an All-Star closer for the Cardinals, one who recorded 48 saves with a 2.10 ERA in 2015. He owns a career 2.99 ERA and 121 saves in 328 appearances, all with St. Louis, and his rate of 12 strikeouts per nine innings is awfully appealing in today's game that prioritizes relievers with swing-and-miss stuff.

Rosenthal does struggle with command at times, and his rate of four walks per nine innings - which inflates his career WHIP to 1.305 - has always been a concern. But he's a big-time power arm with experience pitching late in games, including the postseason (where he sports an 0.69 ERA and seven saves in 23 appearances).

The Nationals have been intrigued by Rosenthal for some time, and they were among the teams that scouted him last week during a showcase in which his fastball reached 99 mph. That helped convince club officials he's healthy again and ready to return to his top form.

With Sean Doolittle already established as an All-Star closer, the Nats can slot Rosenthal into the primary setup role, essentially taking over the spot Ryan Madson held from July 2017-August 2018. Rosenthal also would easily slide into the ninth inning if and when Doolittle is unavailable.

Along with fellow right-hander Kyle Barraclough, who was acquired from the Marlins earlier this month, the Nationals have taken early steps to remake their bullpen after they traded Madson, Brandon Kintzler and Shawn Kelley over the summer, and watched Kelvin Herrera and Greg Holland become free agents this week.