Can key midseason pickup Madson do it again in 2018?

As we transition into offseason mode here, we're reviewing each significant player on the Nationals roster. We continue today with Ryan Madson, whose midseason arrival helped transform the Nats' struggling bullpen into a strength.

PLAYER REVIEW: RYAN MADSON

Age on opening day 2018: 37

How acquired: Traded from Athletics with Sean Doolittle for Blake Treinen, Jesus Luzardo and Sheldon Neuse, July 2017

MLB service time: 12 years, 155 days

2017 salary: $7.5 million

Contract status: Signed for $7.5 million in 2018, free agent in 2019

2017 stats: 5-4, 1.83 ERA, 60 G, 2 SV, 59 IP, 38 H, 12 R, 12 ER, 2 HR, 9 BB, 67 SO, 4 HBP, 0.797 WHIP, 1.9 WAR

Quotable: "Awesome. Awesome. Not just what he brings for us on the mound, but he's one of the leaders in that bullpen, with everything he's been through in his career and the stuff he's accomplished and the postseason teams he's been on. He has a very calming presence." - Doolittle on Madson

2017 analysis: When the Nationals needed major bullpen help this summer, they knew where to shop. They had long been fans of Madson, going back to his days as an anchor of the Phillies' championship bullpen, and they were keen on trying to acquire him now from the A's. And when Doolittle was added to the package, both Oakland late-inning arms found themselves joining a first-place club in Washington.

Madson was enjoying the best season of his career, but it was a long and winding path to get there. He missed three seasons while recovering from Tommy John surgery, then finally found a program that worked for him, one that was built in part on electric recovery treatment. The end result was a reborn pitcher and utterly dominant stuff.

Madson's average fastball velocity this season was 96.1 mph, the highest it had been since 2009. That, combined with a new curveball that became his No. 2 go-to pitch, helped the right-hander morph into a new pitcher, one that not only stayed healthy but was successful against hitters from both sides of the plate. (Left-handed batters had a .506 OPS against him, down 200 points from his career mark.)

With Doolittle closing, Madson settled into the eighth-inning role in Washington and thrived. He was unscored upon in his first 12 appearances with the Nationals, striking out 17 while issuing only one walk. He missed a little bit of time in late August with an odd finger strain that actually seems to have emanated from his forearm. But he returned strong and surrendered a hit in only two of his final seven games.

2018 outlook: Among the biggest selling points on Madson was the fact he was already signed for the 2018 season, ensuring he'll remain a key part of this remade bullpen. Which isn't to say he's a sure thing.

Given his injury history and advanced age - he'll turn 38 before next season's end - Madson has to be watched closely. Former manager Dusty Baker was careful not to overuse him down the stretch this year, and new skipper Dave Martinez will need to take that into consideration as well. And given the fickle nature of relievers, a change in performance from year to year should never come as a surprise.

But give Madson credit for finding a program that works for him and re-establishing himself as one of the game's best relievers. If he can keep himself healthy and if he can continue to command that fastball-curveball combo, he has the ability to continue to be highly effective and now be a force for the Nationals over an entire season instead of a mere 2 1/2 months.