The Mariners' rotation, like the rest of the team, has been constantly evolving throughout 2011. The fact that three of the opening day (or opening week) starters remain in the starting five suggests false consistency.
Felix Hernandez, Jason Vargas and Michael Pineda have been consistent, rarely missing starts, but the other two spots have been thoroughly cycled.
It's not abnormal for the fifth and sometimes fourth spot to change up as the year progresses, but it is arrhythmic to trade away two of your starters at the trade deadline.
In the Mariners' circumstance, it was definitely the right decision, but since then, no pitcher has effectively stepped up and solidified a spot with eyes on a spot in next year's rotation.
We can be nearly certain that Felix, Pineda and Vargas will retain their posts, so the best way to look at what next year's rotation might look like is to rank the top five candidates for the four and five spots.
In what's essentially common knowledge now, the reason GM Jack Zduriencik and the Mariners drafted Danny Hultzen instead of Anthony Rendon is because of Hultzen's potential major-league readiness.
That means they want him starting next year.
There are other prospects in the system who have more experience, but Hultzen shut down college hitting and has the most potential of any other Mariners' pitching prospects. He's also a lefty—a nice complement to the right-handers Felix and Pineda.
Jack Z has actually come out and said Hultzen will have a good shot at hitting the starting rotation, as long as he doesn't botch his Spring Training trial.
It's a little bit difficult to distinguish between some of these guys vying for the spot.
Most of them are having decent outings, eating innings and proving their worth, but there hasn't been a candidate who has blown people away with his potential.
The reason, however, that Beavan trumps Furbush and Vasquez is mostly due to the major discrepancy in ERA.
Beavan has maintained a respectable 4.32 ERA and a 1.31 WHIP through 12 starts in his first major league year—something with which both Furbush and Vasquez have struggled.
Manager Eric Wedge has communicated that he likes the command Beavan has demonstrated, which is a good sign for a young pitcher looking to make the rotation. Young pitchers often face command issues which prevents them from reaching full capability. Since Beavan has already shown he can put the ball where he wants, he's a step ahead.
Furbush isn't as young as Hultzen or Beavan, but he's still green enough to have his prime years ahead of him.
Furbush hasn't exerted much dominance over hitters, but he's nearly as valuable as Doug Fister was to the Mariners during the first half of the season.
Fister (who was traded away to acquire Furbush, along with Francisco Martinez, Casper Wells and Chance Ruffin) pitched pretty well for Seattle.
His record with the Mariners (3-12) is not indicative of how well he pitched. That came from the misfortune of pitching with the Mariners hitting behind him. He's 4-1 since joining the Detroit Tigers, with a 2.64 ERA.
Furbush is just 1-3 since joining the Mariners, but maybe next season he'll experience a turnaround similar to the one Fister saw.
Anthony Vasquez is the other starter who's been getting starts as of late. His first few didn't go so well, as he racked up a 9.00 ERA, but last night, he looked a lot better, giving up just two runs over six innings.
It's unlikely that Vasquez will earn a spot in the starting rotation for 2012, but he'll be on call for sure. If the Mariners fall out of contention early enough that they want to trade their starters again, space could be made for Vasquez.
Tom Wilhelmsen has done a lot for the Mariners in relief this season. The big debate surrounding him is whether or not he'll transition to the role of starter for next year.
He left the majors to work on that conversion in Double-A, but it remains unclear if Wedge will follow through with the project.
Wilhelmsen didn't pitch as well as a starter down in Jackson, but that could just be due to a temporary lapse due to a higher work-rate. He could be bumped up ahead of Vasquez and possibly even Furbush and Beavan if he can return to the form we saw while he was coming out of the bullpen.
It's unlikely that Wilhelmsen would ever be ahead of Hultzen in the rotation, but there are two spots open for next year. That fifth spot will be subject to intense competition by not only these four pitchers (assuming the fourth goes to Hultzen), but also several other pitchers who heat up during the 2012 season.