Joe Nathan Surgery Leaves His Career, Tigers Bullpen in Flux

If you haven't heard the latest on Joe Nathan, it's not good. As the Detroit Tigers announced Thursday morning, the veteran closer is done for the year.

Be prepared to say goodbye to Nathan's career. And while you're at it, you might also want to cast a wary eye on how Detroit's bullpen looks without him. 

Where the former is concerned, the 40-year-old Nathan isn't tasked with an easy road to recovery. He has a torn ulnar collateral ligament in his right elbow that will require the second Tommy John surgery of his career, and he also has a flexor pronator tear.

No need to tell Nathan, he of the 377 career saves, that none of this sounds good. He knows the score.

"I know this is going to be a long grind," he said, via Dave Hogg of Fox Sports Detroit. "I've had Tommy John surgery before, so I know what I'm facing there. But this time I have also torn the flexor, so it is a bigger deal. I'm just going to be patient and do what I need to do."

To his credit, Nathan also said he isn't giving up. He told Bob Nightengale of USA Today he's not thinking about hanging up his spikes just yet:

For what it's worth, Nathan making a comeback may actually be possible.

It's harder to come back from a second Tommy John surgery than it is to come back from just one, but it can be done. And though 2016 will be Nathan's age-41 season, instances of 41-year-old relievers working heavy workloads is actually fairly common. Like John McClane, old relievers die hard.

But that's pretty much the extent to which we can kid ourselves about Nathan's long-term future. Because if Nathan's road to recovery doesn't force him into retirement, baseball may do it for him. 

It's unlikely the Tigers will pick up his $10 million option for 2016. So if and when he does feel ready to return, he'll be trying to sell teams on the idea of picking up a 41-year-old fresh off a second Tommy John surgery who also pitched to a disastrous 4.81 ERA the last time he was healthy in 2014.

Player	IP	ERA+
Mariano Rivera	1283.2	205
Billy Wagner	903.0	187
Joe Nathan	917.0	150
Hoyt Wilhelm	2254.1	147
Dan Quisenberry	1043.1	146

So don't hold your breath in hopes of seeing Nathan on the mound again. It's probably not happening.

If this is indeed the end for Nathan, then the book is about to be closed on one of the greatest relief pitching careers in history. His 377 saves are the seventh-most all time. He checks in at No. 11 in Wins Above Replacement among his fellow relievers. And among relievers with at least 900 innings pitched, Nathan's adjusted ERA of 150 ranks behind only Mariano Rivera and Billy Wagner.

With creds like these, Nathan is going to have an argument for induction into the Hall of Fame when his time comes. But that's also a matter for another day. In the meantime, a more pressing matter is how the Tigers bullpen is going to survive without Nathan.

Carlos Osorio/Associated Press

On the surface, no, it doesn't look like losing Nathan for the season is going to kill Detroit's bullpen.

If anything, it looks more like addition by subtraction. Though Nathan saved 35 games last year, it's no secret he really was as vulnerable as his 4.81 ERA would lead you to believe.

FanGraphs can show he lost some velocity off his fastball. To make matters worse, command struggles that surfaced in 2013 got even worse, as Nathan walked more than four batters per nine innings.

Nathan might have been able to improve on these problems in 2015, but he didn't give off strong comeback vibes with his performance in spring training. He had a 4.63 ERA in 11.1 innings, striking out eight and walking four. Though spring training isn't the best proving ground, he didn't look fixed.

But at the least, Nathan's (seemingly) eventual return could have helped the Tigers bullpen from a depth standpoint. And given the current state of the bullpen, not having his extra arm to look forward to is worth at least some concern.

Detroit's bullpen entered Thursday's action with a 3.76 ERA in 38.1 innings. That's not bad, but it's not good either. It might also be a bit lucky. Per FanGraphs, Tigers relievers own the third-lowest strikeout rate in the league, which typically isn't the best recipe for quality relief work.

To boot, this has been a shared problem.

Carlos Osorio/Associated Press

Aside from Nathan and his small-sample-size 27.0 K/9 rate, every reliever the Tigers have used this year came into Thursday with a K/9 rate below the reliever average of 8.4. One player chiefly responsible for this also happens to be the guy who looks like the best of the bunch: Joakim Soria.

Though Soria is holding down Detroit's closer role with a 1.35 ERA and five saves in eight appearances, he hasn't been overpowering. His 5.4 K/9 is well below the league average, and it's no mirage. His swinging-strike rate of 3.6 percent puts him among the five least-whiffable relievers in baseball.

What's allowing Soria to survive is a suspiciously low .105 batting average on balls in play. The same goes for the rest of Detroit's bullpen, as its .239 BABIP is the fifth-lowest in baseball. Even in light of the Tigers' much-improved defense, that's something that reeks of unsustainability. 

In so many words, this is a bullpen that could soon be wishing it had some guys who can miss bats. And as easy as it is to downplay what Nathan did in 2014, he was halfway decent at that with an 8.4 K/9 and a 9.2 swinging-strike rate.

Without Nathan to turn to for help in the strikeouts department, Lynn Henning of The Detroit News may be right in thinking hard-throwing right-hander Bruce Rondon needs to be the guy who fixes Detroit's bullpen. And while that's not a false hope based on Rondon's electric arm, it may be stretch based on his control. With a 4.9 BB/9 rate in the minors, he has a history of not knowing where the ball is going.

If it wasn't already likely that general manager Dave Dombrowski was going to have to keep his eye out for relievers on the trade market at some point this summer, it is now. With Nathan out of the picture, the needs for depth and for a guy who can miss bats could loom for a while.

In all, here's what we're saying today.

Fare thee well, Joe Nathan's career. Hello again, Tigers bullpen drama.

Note: Stats courtesy of Baseball-Reference unless otherwise noted/linked.

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