The only possible argument against this acquisition and this deal is Nathan's age. He turned 39 in November. But he is coming off one of the finest seasons of a terrific career.
Nathan had 43 saves in 46 opportunities for the Texas Rangers in 2013. He had an ERA of 1.39 and a WHIP of 0.90.
Even better than that, in the context of his career, Nathan made a successful transition in his approach as he lost velocity. He relied increasingly on movement and location and offspeed pitches. The result was a resounding success.
"I think you just learn to try not to do more than you're capable of," Nathan said during an in-season interview with MLB.com. "I know my fastball is not the same as it was, but I've learned to get comfortable with a two-seam fastball and kind of move things around a little bit.
"It's still the same old game about getting ahead [in the count] and staying ahead. It puts them more on the defensive. So throw strikes, don't give them an opportunity to sit on one pitch and get comfortable. That hasn't changed.
"I think after being in this game a while, you hope you learn things along the way, so when your arm is not as strong, you can get guys out other ways."
Nathan throws two types of breaking balls and is increasingly reliant on a very good two-seam fastball. Last season, he was throwing in the low-90s, instead of the mid-90s he once reached, but he still had swing-and-miss stuff, recording 73 strikeouts in 64 2/3 innings.
"I just try to give them a different look," Nathan said. "You know, these guys are used to me throwing mid-90s and probably a little straighter. I was able to throw hard and then mix in breaking balls with that. That's what made me tough then. Now, I just want to move it around a little bit, keep them guessing."
The hitters were still guessing, and not necessarily correctly, against Nathan in 2013.
There is no overstating how good Nathan's career has been. Among closers with 200 or more Major League saves, he has the highest career save-conversion percentage, 89.97. The recently retired Mariano Rivera, widely considered the best closer of all time, successfully converted 89.07 percent of his save opportunities.
Nathan has been exceptional since he took over the closer's role for the Minnesota Twins in 2004. He lost 2010 to Tommy John surgery and had some typical inconsistency coming back the following season. But his work with the Rangers over the last two years has completely re-established his career and his value.
There are other options on the market, and cheaper ones. But this is the right move for the Tigers, who remain in a win-now position.
With Ian Kinsler in the mix following the trade of first baseman Prince Fielder, the Tigers still boast a potent lineup. Even with the trade of Doug Fister to the Nationals, they also have one of the best pitching rotations in the game, with Justin Verlander, 2013 AL Cy Young Award winner Max Scherzer, Anibal Sanchez and Rick Porcello. Lefty Drew Smyly is expected to move from his setup-relief role to the rotation.
The Tigers found a replacement for Smyly's bullpen spot in the Washington trade, getting Ian Krol, who worked well in his first Major League season. Now, the signing of Nathan could allow them to re-sign 2013 closer Joaquin Benoit to the fill setup role in which he was so successful from 2011-12. As an added bonus, there will now be time to groom flame-throwing Bruce Rondon as the Tigers' closer of the future. Rondon ended the 2013 season with elbow soreness but is expected to be fully healthy for the start of Spring Training.
One way or another, the bullpen was the Tigers' shortcoming in 2013. They have been in the postseason for the last three years. They have established themselves as consistent winners. But they are still looking for the biggest prize of all.
With all this talent on hand, in bolstering the bullpen, why not go for the best available closer, one of the genuine elite closers? The Tigers decided to go with Nathan. On a team that is built to win now, he is the right man for the closer's role.