September for rookies is similar to what boxing once referred to as the "championship distance." It’s unknown territory from the known past that tests and separates through increased demands on the inexperienced.
Mariners closer Edwin Diaz, in so many words, acknowledged that extra distance bit him down the stretch. He closed the season by allowing five runs and 10 hits over 6 2/3 innings in five appearances.
That span, over 11 days, included a loss and two blown saves just when the Mariners were mounting an uphill charge in hopes of securing their first postseason berth in 15 years.
"I learned a lot," Diaz said quietly last Saturday night after giving up the winning run in a 9-8 loss to Oakland that ended the Mariners’ postseason hopes.
"I didn’t pitch (before) in September. My arm was tired, but I set my mind to keep fighting and to try to help the team to win. This month was tough on me because I was a little bit tired."
It remains a remarkable year for Diaz, who began the season as a starting pitcher at Double-A Jackson. He switched to bullpen duty in mid-May, gained a two-step promotion to the big leagues in early June and became the closer in August.
"Our (player-development) people deserve all the credit," manager Scott Servais said. "They identified what he’s been able to do. And Eddie, he’s enjoying his experience so far. He’s always got a smile on his face.
"He’s not really letting anything get to him. Also, his head hasn’t gotten any bigger (as a result of his success). He’s the same guy who showed up here a couple of months ago."
Diaz, 22, compiled a 2.79 ERA in 49 games while recording 88 strikeouts in 51 2/3 innings. He had 18 saves in 21 chances. His sabermetric peripherals were eye-popping: a 2.04 FIP (fielder-independent pitching) and a 146 ERA+.
He just wasn’t the same in September, which shouldn’t be surprising. He never pitched past Sept. 7 in four previous professional seasons following his selection in the third round of the 2012 MLB Draft. Until last year, he didn’t pitch past August.
"The finish to some of his pitches (wasn’t there)," Servais said. "We talked about it when he first came up, we had to be careful in how much we used him; leaving a little bit in the tank at the end.
"There were a few outings when we had to go get him in the eighth inning. That’s just where we were at. We had to win that game. That does put some extra stress on it."
As Diaz wore down, he tried to compensate by spotting the ball instead of just letting it rip. That approach often backfired.
"I think he tries to feel for it," catcher Mike Zunino said. "He’s got good stuff. So for him to go out and try to feel for it, instead of just letting it go, that can be an issue."
Another factor down the stretch was a growing familiarity, particularly among division opponents.
"I think you also have to give credit to people around the league," Servais said. "Once they start seeing him, and understanding how he does it, they’re going to approach him a little bit differently. I think you saw a little bit of that as well."
It all amounted to a learning process for Diaz, and one of the big lessons is the championship distance is different. Now he knows.
"Next year," Diaz said, "I need to try to do better."
Right-hander Taijuan Walker indicated he is leaning toward surgery as a permanent solution to the troublesome tendinitis in his right foot.
The problem limited Walker in several starts and caused him to spend a month on the disabled list. It stems from the stress that Walker puts on his arch as he pushes off the rubber and is aggravated by his flat feet.
While treatment appeared to correct the problem over the final month, Walker acknowledged concern over a recurrence in the future. Any decision on surgery must be made soon because the anticipated recovery period is three-to-four months.
***Reliever Steve Cishek plans to undergo surgery to repair a small tear in the labrum of his left hip. He pitched the final six weeks with the injury after treatment lessened its impact during time on the disabled list.
***Reliever Tony Zych appears headed for surgery to address the tendinitis in his rotator cuff, which limited him to 12 appearances. The anticipated recovery time for the procedure is a two-to-three months.
As things now stand, the Mariners will have the 18th pick next June in the MLB Draft, although they could move up if clubs ahead of them forfeit their first-round picks by signing free agents who receive qualifying offers from their former clubs.
The draft order is determined through a reverse order of the records for all 30 clubs, i.e., the club with the worst record, Minnesota, gets the first pick.
The first 10 picks are currently protected from the penalty of signing a free agent with a qualifying offer. Those clubs forfeit their second pick if they sign such a player.
There is further uncertainty at this point because the labor agreement is expiring. While a new agreement is generally anticipated shortly after the World Series ends, it could contain new provisions regarding the draft.
While Lo-A Clinton posted the best record this season in the Midwest League, it landed only one player in Baseball America's rankings of the league's top 20 prospects.
Left-handed pitcher Luiz Gohara, 20, was No. 11 after going 5-2 with a 1.82 ERA following his June 30 promotion from Short-A Everett.
"Gohara appeared more athletic on the mound this season," Baseball America reported, "making his delivery more repeatable and helping his control.
"He walked 3.3 batters per nine innings, which is a huge improvement from previous efforts, while striking out 60 in 54.1 innings."
The Mariners signed Gohara, a Brazilian native, for $800,000 in 2012. He becomes Rule 5 eligible this winter, which means he is likely to placed on the 40-man roster in November.
Bob Dutton: @TNT_Mariners