It was a breakout year for Yonder Alonso in 2017, as he recorded career-highs in home runs (28), on-base percentage (.365) and slugging percentage (.501). Alonso has generally been able to get on base at a good rate with a career .340 OBP, but it was the power surge that was the most surprising for him. Splitting the season between Oakland and Seattle, Alonso hit 28 home runs in 521 plate appearances — matching the total number of home runs he hit over the last five seasons and 1,735 plate appearances.

Alonso hit well enough to earn his way to his first All-Star Game and a two-year $16 million contract with the Cleveland Indians in the off-season, but the question is: how will he hit in 2018?

At age 30, has Alonso turned a corner and become a good fantasy first baseman, or was 2017 just a flash in the pan?

Will the real Yonder Alonso please stand up?

First off, a look at Alonso's splits between Oakland and Seattle show he had a big first half with the Athletics and dropped off some in the second half with the Mariners. After compiling a .369 OBP and .527 SLG with 22 HR in his first 100 games in Oakland, Alonso had a .353 OBP and .439 SLG with six HR in his final 42 games.

The decline in power during the second half makes sense as Alonso had a 45.5% fly ball rate in Oakland — 12.2% higher than he hit in 2016 and 11.2% higher than his career rate. He still had a high fly ball rate in the second half, but at 38.2% it was much closer to his career norm.

Further casting doubt on his ability to repeat his HR output is his considerably inflated HR per fly ball rate. After having no higher than a 7.8% HR/FB rate over the previous five seasons, Alonso sported a 19.4% rate in 2017 — 5.7% higher than the MLB average.

While Alonso will likely not hit 25 or more home runs this year, there are signs that he will be able to sustain some of that power moving forward. His batted ball percentages showed he was hitting fewer ground balls and more fly balls, while also making harder contact than in previous seasons.

It seems like Alonso has done something to change his approach at the plate which is translating into more HR. Something around 13 to 17 HR seems like a reasonable projection for Alonso, which would still be an improvement over the five to six HR he averaged per year before 2017.

What Alonso has done fairly consistently throughout his career and should continue to do in 2018 is get on base at an above-average rate. He has a career .340 OBP and has now had at least a .360 OBP twice in the last three seasons. There were only seven first basemen in MLB in 2017 with a higher OBP than Alonso, and only two of them were in the American League. Alonso was also one of only four American League first basemen with at least a .360 OBP and one of only seven with at least a .350 OBP.

Hosmer and Morrison are still free agents as of the writing of this article and with Santana moving to the National League after signing with the Phillies, Alonso becomes a more valuable commodity for AL-only leagues.

Alonso also now joins a much more potent Cleveland Indians offense that averaged 5.05 runs per game, as opposed to the below-average Oakland and Seattle offenses which scored 4.56 and 4.63 runs per game respectively.  He made most of his plate appearances out of the two- and five-spots in the batting order last year and he will likely do so again in 2018. This means plenty of run-scoring and RBI opportunities for Alonso, as Cleveland batters in the first through fifth spots of the order averaged 103.4 runs and 94.8 RBI in 2017.

The bottom line on Yonder Alonso is that he will be a good-not-great fantasy first baseman in 2018. In mixed leagues, he will likely be waiver-wire fodder that will periodically get added to a roster to fill in for an injured player. Alonso will provide the most value in AL-only leagues where he has the potential to be a top-15 first baseman or OBP leagues where he can be a top-25 first baseman.

More 2018 Player Outlooks