A year ago, Jerad Eickhoff put the finishing touches on a breakout season. He pitched six innings in the Phillies' final game of 2016, struck out eight, and carried a 3.65 ERA into his guaranteed rotation spot for 2017.

This month, Eickhoff has had more time to think. His season ended Aug. 30 because of inflammation in his chest that affected nerves in his fingers. He has studied numbers and videos from starts earlier this season. He has questioned his routine between starts and fixated on mechanical issues that plagued him.

He will not start from scratch in 2018, but he will have to prove himself again in spring training. A 4.71 ERA in 128 innings, marked by inconsistent stretches, will do that.

"It's a learning experience," Eickhoff said this week. "I am learning more about my body. I hate that I have to go through it like that. But seasons like this — frustrating times like this — create an opportunity to learn. It's really going to help me next year."

The Phillies, after last season, harbored hope that Eickhoff could be more than a fifth starter. Their path to contention is dependent on a few of the young arms advancing. Aaron Nola did that in 2017, and 2018 will be a test of his true place in the future. Eickhoff's 2016 is proof that one fine season does not create a rotation mainstay.

"Nobody's locked in, other than Nola," Phillies manager Pete Mackanin said.

So Eickhoff, a cerebral pitcher, is left with some pressing thoughts. His fastball velocity cratered in July and August, something Eickhoff attributed to a back injury and subsequent numbness in his fingers.

He wants to make one more adjustment for 2018 that could help his arm stay fresher: Throw less between starts. He applied that change in June, but that was around the time of the back injury.

"It was just playing out there in right field," Eickhoff said. "The number of throws I would throw and at what intensity. Just backing that off. Knowing that when I feel good, that's when I need to stop throwing."

Eickhoff's fastball averaged 90.3 mph in 2017, according to Major League Baseball's pitch data. It was 91.6 mph in his previous two seasons.

"I did my own personal research, looking at starts," Eickhoff said. "My velocity was actually fine for the first half of the year."

His fastball averaged 90.9 mph in his first 12 starts, before a game in Boston when his back hurt. In April, he threw his fastball at an average of 91 mph.

The velocity is important. Even more important, especially with a tick or two missing, is location.

"As far as velocity and fastball, I'm not concerned," Eickhoff said. "The first half of the season, I was healthy. Things were coming out good. It was just mechanically, the direction was off. That's an easy fix."

He will not be able to apply it until this winter, when he follows his normal offseason throwing program. A critical season looms.

"People said last spring training I had the spot," Eickhoff said. "I really don't see it that way. I go into this spring the same as I would any other year. I'm going to try to work for it."

Extra bases

Hector Neris has converted his last 19 save chances, the longest such streak for a Phillies pitcher since Jonathan Papelbon had 19 straight spanning 2014-15. Neris owns the second-longest active streak in baseball. … The Phillies are off Thursday before the New York Mets come to Citizens Bank Park to finish the season. Ben Lively, Henderson Alvarez and Nick Pivetta will pitch. The Mets will throw Matt Harvey, Jacob deGrom and Seth Lugo. Noah Syndergaard is scheduled to pitch in relief, possibly Friday.