Mariners sign Luke Weaver. How can the Mariners get the most out of a 6-man rotation?

Jerry Dipoto stated that the Mariners had intended on rolling with a 6-man rotation for the remainder of the year. The unfortunate injury to Emerson Hancock put a wrench in that plan. They have since turned their attention to the free agent market and signed Luke Weaver to fill that void. With Bryan Woo on an innings limit, does a 6-man rotation make sense still? Is there a different type of 6-man rotation that Servais could make use of, that will put the best Mariners starters out there every game as well as limit Bryan Woo’s innings down the stretch.

How should the Mariners use Luke Weaver?

The Mariners signed Luke Weaver in hopes of him contributing down the stretch. When you look at his numbers, they are very unimpressive this year. He made 21 starts and compiled a 6.87 ERA. His walk and strikeout numbers weren't awful, but if you look at his baseball savant page, he gave up a lot of barrels and hard contact. On the positive side, his spin rates are impressive with his fastball in the 85% percentile. Maybe there is something there the Mariners analytics think that they can work with.

Bryan Woo was activated to start game 2 versus the White Sox. After that game, the Mariners have 36 games remaining. If you used a 5-man rotation that means that every starter will have 7 starts and your #1 starter would have 8 starts. If you used a 6 man rotation, that means that every starter will have 6 starts. In this situation, you would basically take away 4 starts from Castillo, Gilbert and Kirby and give it to Miller, Woo and Weaver. I am not a fan of taking starts away from those guys!

I am okay with the Mariners planning to limit Bryan Woo’s innings, I actually think that this is a good idea. He has had arm issues in the past and has already thrown almost twice as many innings as he has in any single season, but is a 6-man rotation with Luke Weaver really the best idea, down the stretch, playing for playoff games?

I don't think so.

The Mariners don't need to limit Castillo, Kirby, or Gilbert’s innings, so why cut their number of starts made? Resting your starters down the stretch could potentially pay off come October, but for that to matter, you have to get to October. You have to have your best team on the field a majority of the time.

I think the best way to limit Woo’s innings while not taking any starts away from your 3 big starters is to piggyback Woo and Weaver on the same day. Let Woo throw 3 or 4 innings and hope that Weaver can give you 3 effective innings. This could be an effective way to still give Castillo, Gilbert and Kirby all of their starts, limit Woo’s innings and it could give the bullpen a little bit more of a rest day if Woo could occasionally go 4 and Weaver go 3 or 4 or vice versa.

The Mariners did claim Luke Weaver last October, so there is obviously something there that they like with him. It will be interesting to see how they utilize Luke Weaver and if they can get the most, not only out of him, but out of Woo and the rest of the rotation.