Mariners Breakdown: A Realistic Look at Yonder Alonso

TORONTO, ON - JULY 26: Yonder Alonso
TORONTO, ON - JULY 26: Yonder Alonso /

The Mariners acquired 2017 All-Star first baseman Yonder Alonso from the Oakland Athletics for Boog Powell. Yonder Alonso has had, by all accounts, a breakout season. His career high in home runs before this year was 9 in 2012 with the San Diego Padres. He currently sits at 22.

As someone who has followed and covered the Padres for most of my life, I have seen a lot of Yonder Alonso. Allow me to take a realistic look at the Mariners acquiring an All-Star from this year.

On the surface, his numbers are great. As mentioned, he has 22 bombs with an .896 OPS. His first half numbers were borderline ridiculous as he had 20 home runs in 79 games along with a .934 OPS. and a .275 average. However, in the second half, he has just two homers in 21 games with a .230 average and a .733 OPS.

He was with the Padres from 2012 to 2015. He averaged seven home runs a year with a .271 average and a pedestrian 106 OPS+. He was a decent contact hitter but not your typical hitting first baseman. He averaged 1.4 WAR in his four seasons with San Diego.

Defensively, in his five previous full seasons, he averaged about five Defensive Runs Saved per year at first base, which is very respectable. He has had a solid glove at first. He probably won’t win a Gold Glove any time soon but he certainly is not a liability at first.

Now to break down his hitting. His career average fly-ball rate percentage (FB%) 34.1%. This season, it has jumped to 45.5%. This means he is elevating his swing more to get more lift on the ball. Obviously, this has contributed to his home run spike. He also has changed his approach, trying to hit the ball to all fields instead of flying open and pulling the ball. His career average pulling percentage for batted balls is 38.4% and his opposite field batted balls is 26.5%. This season, his pulling percentage is slightly down at 38.1% and his opposite field hitting is up to 28.6% (these numbers per FanGraphs).

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Are his power numbers here to stay? I would not expect him to hit 20+ home runs every season. The Mariners did not acquire him to finally be a mainstay they have looked for at first base since perhaps Richie Sexson or John Olerud, as he is only a “rental” at this point as he will be a free agent after the season. He will likely serve as a platoon bat. He is a lefty that is hitting .286 with 18 home runs against right-handed pitchers this season. He struggles against lefties (.188, 4 HR). That’s no problem since the right-handed Danny Valencia is hitting .309 with a .919 OPS against lefties.

In essence, the Mariners have found a great platoon at first base for the remainder of the season. Is he the missing link that will put them over the edge and into the playoffs? I personally do not think so, because the M’s have bigger holes in their pitching staff. The acquisition of Alonso to me says that Seattle is hoping to bludgeon teams to death since the pitching is unreliable.

Next: Mariners Progress Report: Knocking on the Door

All in all this was a solid pickup. If he can hit above .270 against right-handers with an .800+ OPS and play a decent first base, it will be worth it.