A couple years in the Oakland lineup pushed Marcus Semien to respectable power numbers with a middling batting average and double-digit stolen bases year after year. He popped 27 long balls in 2016, despite a .238 average. However, he only hit 25 home runs in the next two seasons, but then 2019 hit. And so did Semien. He played all 162 games, hit a career-best .285 and also posted career highs in home runs (33), runs scored (123), runs batted in (92), ISO (.237), on-base percentage (.369) and slugging percentage (.522), among others. So, after a year of career-bests, regression was likely. However, the extent of which it happened was surprising.

Across 53 games, he hit seven home runs, but his .152 ISO reverted back to his ways prior to 2019 (.155). In fact, all Semien really did was regress to the mean, and the mean being his career numbers prior to the 2019 season. So, yes, Semien regressed compared to his 2019 season, but really, he just returned to what he was over the past four years. Take a look here:









Barrel Rate

Semien (2015-2018)









Semien (2020)









Courtesy of FanGraphs & Baseball Savant

His drop off from 2019 isn’t far expected, considering that he had a longer track record of the 2020 version of himself compared to the 2019 version. Now, there’s room for growth in 2021, especially given his situation. However, there are some things that need corrected.

His launch angle jumped, but as mentioned earlier, the contact was less impactful. From 2015-2019, per Baseball Savant, he got under the ball no higher than 32.6 percent. Well, in 2020, it was 38.5percent. When you look at his pop up percentage, his previous career high was 8.8 percent in 2018. In 2020, it was a whopping 12.4 percent. Breaking pitches caused pop ups for Semien quite regularly. In 2019, his launch angle against breaking stuff was 16 degrees, and the average exit velocity was 85.5miles per hour. However, in 2020, the launch angle jumped to 25 degrees, but the average exit velocity fell to an underwhelming 82.9 miles per hour. Ouch.

His strikeout rate jumped back above 20 percent in 2020, largely due to some added whiffs from recent years, but the mark that really jumps off the page is his 83.4 percent zone contact rate that is his lowest mark since his rookie year in 2013 where he only logged 69 at-bats. Again, breaking pitches were a culprit here, but in fact, the increased whiffs were substantial across the board.

Overall, Semien has never boasted an elite power profile. Even in his power-packed 2019 season, his average exit velocity and barrel rate came in at the 41st and 57th percent respectively. His 2020 season was a slight step down to the couple of years prior to his breakout 2019 season, but he’s not as bad as he was in 2020.

Now, he leaves Oakland and heads to Toronto on a one year, $18 million contract where some developments have certainly helped his fantasy value for the 2021 season. He’s going to hit in the upper-third of the lineup for the Toronto Blue Jays, and will have the luxury of Bo Bichette , Vladimir Guerrero Jr. and Teoscar Hernández driving him in. There were thoughts Cavan Biggio would hit second, and Semien would get pushed down the lineup, but appears that Biggio is the slider, and Semien is the riser. Additionally, he’s expected to be their starting second baseman, so after about a week and a half, he’ll be eligible for both shortstop and second base. Love it.

I still envision strikeouts being somewhat of a concern for Semien in 2021, as he likely hovers around 18 percent this year. However, he has an everyday gig in the lineup -- thanks hefty contract! -- and as long as he doesn’t falter,  2021 figures to be the third time in his career he hits at least 20 home runs, and the second time he scores 90 or more runs. He’s not getting any cheaper in drafts, aided by both the signing in Toronto, and his continued presence near the top of the lineup throughout spring.

Don’t expect a .270 batting average from Semien in 2021, but 25 homers, 10 stolen bases, and 90+ runs is very attainable for the former Oakland infielder in his first season with the Blue Jays.


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