Marcus Semien has taken a step back defensively as a second baseman in his first season with the New York Mets. Over the first 110 games of 2026, he is tied for the second-worst defensive second baseman with outs above average and runs prevented of (-6) and (-4), respectively.

The statistics are a far cry from the previous three seasons with the Texas Rangers. Semien ranked as the second-best defensive second baseman from 2022 to 2025. During the span, he accumulated a total of 49 outs above average and 36 runs prevented.

The difference in his defensive performance between the two organizations is their defensive alignment. During Marcus Semien’s tenure in Texas, the Rangers employed a defensive strategy called “shading.” MLB.com defines shading as follows:

Shaded: At least one fielder is positioned outside the area of the field they’re typically responsible for. (Example: The SS is “shaded” when playing up the middle against a LHB or toward the 3B zone against a RHB)

Rangers Defense

Texas was in a shaded defensive alignment 33.3% of the time from 2022 to 2025, ranking in the top 10 in the major leagues. That alignment meant that when a right-handed batter was at the plate, Marcus Semien stood closer to second base. 

On the flip side, when a left-handed batter was at the plate, Semien stood closer to the hole between first and second base. Over 90% of Texas shading alignments happened against left handed batters.

A perfect example of this happened on April 22, 2022, when the Texas Rangers were facing the Oakland Athletics. Left-handed batter Tony Kemp hit a baseball into the hole between first and second base. 

Due to the defensive alignment, Marcus only took two to three steps to the left to retrieve the baseball. He delivered a perfect throw to first base with plenty of time to get the batter out.

As a result, he was in the shaded defensive alignment for 1,076 plate appearances during the 2025 season alone. Unfortunately, the New York Mets used the defensive alignment less frequently. They utilized the same alignment on 21.8% of plays in 2026, 21st in the league.

Mets Defense

Consequently, Semien is playing conventional defense more often, which makes it harder for him to play defense. Semien has been in the shaded defensive alignment for 568 plate appearances in 2026.

The change in defensive strategy has put Semien in a position where he has to cover more ground to reach the baseball. On May 21, 2026, Semien stood between first and second base in the bottom of the inning against the Washington Nationals. 

Daylen Lile hit a baseball towards the hole between first and second base. Semien had to take seven or eight steps to get to the ball. Unfortunately, the baseball hit off the heel of his glove for a hit.

Ultimately, New York Mets President of Baseball Operations David Stern needed to do a better job of putting Semien in a position to succeed. New York should have used a shaded defensive alignment more often. That would have put Semien in a better position to field the baseball without having to run as much.

However, if David didn’t want the New York Mets to adjust their defensive alignment, they should have acquired another second baseman.