Marcus Semien: Franchise Shortstop?

Improvements in Semien's Game

Yesterday Oakland A's shortstop Marcus Semien tied his career-high (set in 2015) mark for home runs in a season with his 15th dinger. This particular home run was Semien's fourth-longest of the season and came off former-Athletic Jeff Samardzija. It also helped jump-start an 8-run showing in the Bay Bridge Series opener.

I have not been shy about my excitement over Semien's potential. Call it a man crush. It's been an awesome surprise to see how quickly his defensive competency has caught up to his skills at the plate. It may be a little old now but the heart of Eno Saris' article remains the same: Marcus Semien is now shortstop.

Not only has Semien already matched last season's career-high 15 home runs, but he's already eclipsed last season fWAR with a 1.9. In fact, he's on pace to set career highs in virtually every meaningful statistic.

He has an above average BB/K ratio and his ISO has jumped 70 points. You might point to his extreme home run-per-flyball rate as a cause for concern but the fact that his soft, medium, and hard-hit rates are all normal and his live-drive rate is climbing points to his overall production steading even if his home run rate slips. There may even be more room for improvement seeing as how his BABIP is still nearly 50 points lower than last season.

An underrated aspect of Semien's game isn't measured in on-field production as much is just being on the field. Since the beginning of 2015 Semien is tied for 17th in baseball with 231 games played.

To top it all off the A's have control over Semien through the 2020 season. This has me thinking, amidst another season of transition and the inevitability of more roster churning, has Semien become the A's franchise shortstop?

Since 2004 (the season following Miguel Tejada's departure) the A's have had four different starting shortstops. That's a new shortstop every two seasons. Semien's 2016 is already the fifth best season among the eight since Tejada, and we're not even finished with June. There's a solid chance that at the conclusion of 2016 Semien will have played the best season by an A's shortstop since Tejada. Honestly, I never thought I'd write that.

If Semien reaches the 4-fWAR threshold this season he'll be on the cusp of All-Star level quality which, in my opinion, as a very big win for the A's. Not only is Semien developing into one of the better shortstops in baseball (his 2016 fWAR is tied with Carlos Correa for 7th-best in MLB) but the A's could have an opportunity to sign him to a long-term contract at an affordable rate.

What Could an Extension Look Like?

I took a look at all shortstops since 2004 who were 25-years old or younger who also posted between 4 and 5 fWAR seasons. There were eight, in no particular order: Andrelton Simmons, Hanley Ramirez (4 times), Xander Bogaerts, Manny Machado, J.J. Hardy, Jhonny Peralta, Elvis Andrus, and Felipe Lopez (Machado and Bogaerts haven't signed a long-term deal and Lopez never did, so they will be excluded from this exercise). Four of the above shortstop signed an extension within two years following their 4-5 fWAR season: Ramirez, Simmons, Peralta, and Andrus. Hardy signed a one-year deal following his, then had a couple years of poor performance before eventually signing a 3-year, $40 million deal with Baltimore.

Recent Shortstop Extensions

Player	Under-25 4-5 fWAR seasons	Extension Year	Extension Details
Hanley Ramirez	4.4 fWAR in 2006, 5.2 fWAR in 2007	2008	6-years, $70 million
Jhonny Peralta	4.3 fWAR in 2005	2006	5-years, $13 million
Elvis Andrus	4 fWAR in 2011	2013	8-years, $120 million
Andrelton Simmons	4.5 fWAR in 2013	2014	7-years, $58 million

Ramirez went on to have three more 4+ fWAR seasons before turning 26 and two more after turning 26, all during his contract extension. Peralta posted two 4+ fWAR seasons after turning 26 and none during his extension with the Cleveland Indians. Simmons and Andrus have yet to come close to a 4+ fWAR season.

Conclusion

Right now Oakland has their eyes set on a potential Josh Reddick extension, and that is warranted considering he could be lost forever at the conclusion of 2016. Would it be wise for the A's to start considering locking up Marcus Semien as well?

The history of long-term contracts tells us this isn't a great idea. Not to mention the fact the shortstops above generally never repeated their success prior to the extension. Keep in mind that Andrus and Simmons weren't necessarily bat-first shortstops so fluctuation in their performance wasn't totally unexpected.

If the A's can manage to extend Semien at an annual rate between $7 million and $10 million then it might be a no-brainer decision.