On this week’s edition of The SIS Baseball Podcast, we spoke with New York Times national baseball writer Tyler Kepner about the biggest surprises of the 2021 MLB season.

These are some of the highlights:

The Giants are the biggest surprise, as they were projected to finish below .500 but have cleared 100 wins and are about to conclude one of the best regular seasons in franchise history.

Perhaps the most impressive and surprising thing about the Giants is that their roster is deep. They’ve had an MLB-record 17 players hit at least 5 home runs this season. Their players have been largely interchangeable. If one player sits, another steps in and the team doesn’t miss a beat.

One of the best examples of that is that when the team starts Curt Casali at catcher rather than Buster Posey, the Giants are 42-12.

In the American League, the Mariners were also not expected to be a contender but are within reach of an AL Wild Card spot as their extremely unusual season nears the finish line. The Mariners rank 14th in the AL in OPS, 11th in runs scored, and 8th in team ERA but entered Thursday 89-70 largely due to a 33-18 record in one-run games.

Among the Mariners’ biggest individual surprises is reliever Paul Sewald, who changed his pitching delivery to one with a three-quarter release. Sewald’s fastball averages only 92 MPH, but he’s averaged the second-most strikeouts per 9 innings (14.2) among AL pitchers with at least 50 innings pitched. Not bad for someone who had a 5.50 ERA in four seasons with the Mets prior to 2021.

As Tyler pointed out, the Rays also qualify as a surprise to some extent, though calling a 2020 World Series team a surprise seems a little odd. But the way that they’ve gotten to an AL East title and nearly 100 wins was unexpected.

Tampa Bay traded one of its three top starters from last season’s team (Blake Snell), lost another to free agency (Charlie Morton) and had the other (Tyler Glasnow) for only 88 innings before a season-ending injury. Three of the Rays’ top four pitchers in innings pitched have ERAs over 5.

The Rays lead the AL in runs scored because their lineup is loaded. Of their top 13 players in plate appearances, 11 are above average in OPS+ and the other two hitters are only a smidge below average.

We’ll close with our favorite player stat surprise of 2021, one we’ve shared a few times as the season has moved along.

The Rockies certainly felt Nolan Arenado’s absence after trading him to the Cardinals this past offseason. But that was more so in terms of Arenado’s bat than his glove.

Rockies third basemen (led by Ryan McMahon and Joshua Fuentes) have combined for 24 Defensive Runs Saved this season. Arenado has only 7.

One of the beauties of baseball is its unpredictability. These are just a few of the unpredictable highlights of 2021. Hope you’ll listen to this episode to hear a few more.