Gio Gonzalez is having a bit of a mini-renaissance right now. Since the All-Star Break he has pitched to a 3.00 ERA, holding opposing batters to a .209 / .257 / .358 line. He has gone 5-1 turning a disappointing 5-8 record to a respectable 10-9. Part of it is luck (BABIP down around .245) and part of it is skill (BB/9 down to 2.3, when it had been solidly over 3.0 previously. HR/9 down significantly as well) but it has happened and it begs the question, will Gio be here next year or not?
If you look at it on a strictly 2017 estimate of performance you'd probably say yes, despite what we've seen for the year. Yes, Gio's career has been a on a general slow decline since the Cy Young worthy year he put up in 2012. He's trended being more hittable and striking out fewer and that very basic combination has predictably led his ERA to trend up.* Of course ERA is somewhat a function of the team defense behind him and the relief pitching after him but the xFIP has trended up as well. Ultimately his numbers bounce around a bit as his walks and HRs shift but the fair expectation would be next year would be slightly worse than this year. An xFIP of around 4.00 an ERA somewhere on the 3.70 to 4.30 range.
That's not a terrible range. It puts him in the #3-#4 range for an average NL rotation, and his pay is not onerous at 12 million dollars. You may or may not find that talent level for that price. The combination of those facts should have you take a flier on Gio for one more year hoping for something more toward the 3.70 than the 4.30.
But the Nats don't have an average rotation. They have a very good one that they rely on to carry the team in some fashion. Scherzer, Strasburg, Roark, and Ross, when healthy, push Gio to the 5 hole and while he is and would continue to be an excellent number five, that is traditionally a spot where you try out young talent if you have it. The Nats do have it in Giolito and Lopez. While Gio may be more reliable, the chance at developing talent for million less has got to be tempting to a team that appears to be at it's maximum desired payroll range with some large raises due. Also to be considered is that 2017 is not necessarily a one-off deal. Gio has a vesting option for 2018 if he reaches 180 innings in 2017, meaning the Nats would be on the hook for his 12 million in 2018 regardless of his performance in 2017. How likely is he to reach 180? If he's healthy he should do it. If he misses more than a couple starts he shouldn't. I'd make it a coin flip right now. Since he seems to be slowly declining it's easy to imagine a "worst case" where he pitched to a ~4.40 ERA next year but pitches all year and the Nats are on hook for a pitcher in 2018 who might start to skirt the 5.00s.
When Stras re-signed the balls were set in motion. The 1-4 spots looked set and the payroll got that much bigger. It looked like in order to free up a spot and to get some monetary fliexibility, Gio would be pitching his last games in a Nats uniform in 2016. Maybe the Nats let him walk, or more likely they trade him for something of value. A LH starter on a reasonable contract is worth something decent. But things have conspired since that point in the opposite direction. Strasburg and Ross have had significant injuries which highlight the need for true depth for a rotation. Both Giolio and Lopez (and Cole) have failed to show that they are definitely ready for a rotation role at the start of 2017. After a slide through May and June, Gio has come back with two solid months of pitching.
It's easy to say "keep him" right now. Recency bias abounds in his and Giolito's and Lopez's performances. But we must be more prudent than that. It is very likely Lopez or Giolito will be ready for an extended trail early next year. It is very likely Gio will decline and will be the first one to give up his spot. Do you want to pay 12 million for a place holder? Do you want to gamble that if injuries happen, as they are want to do, that you could be paying 12 million for a nothing in 2018?
In the end I lean toward keep him. I lean toward depth in a pitching staff and given Strasburg's and now Ross' injury concerns I don't want to have to rely on Giolito AND Lopez to fill in. The lefty role matters too if only to give teams a change of look. Also, while it's certainly possible Gio tows the line and the Nats get hooked for another year, it's probably just as likely he pitches himself out of the rotation for one of the young guys (just think how close he might have been to this at the end of June this year) or he sustains a mild injury (or worse) himself, making the vesting option moot. Plus while the worry is he goes 4.40 4.90 the next couple of years 4.20 4.40 is possible too and at 12 million a year that's not terrible. And if he does better and the team has its usual odd season swoon, well you've got a decent trade chip still.
For me the negatives don't outweigh the positives. Things could change if Gio crashes and Lopez or Lito crushes, but beyond that I think we haven't seen the last of Gio. At least for one more year, get ready to sit back, relax, then get frustrated that this game seems to be taking forever as Gio works toward 115 pitches over 6 innings.
*Other fancy stats have trended in the wrong direction too. Hard%, FB Speed, Contact in the zone. It all hasn't gone strongly in one direction, some impt ones bounce around just like BB-rate and HR-rate but there hasn't been anything trending positive. So the overall effect is he's getting worse. Like he should! He's getting older! This happens!