Was anyone a bigger surprise during the 2021 MLB season than Baltimore Orioles center fielder Cedric Mullins?

That's certainly up for debate, but each team had at least one player who surpassed even the most optimistic expectations over the course of the year.

Ahead we've highlighted each MLB squad's biggest surprise in 2021.

For the sake of this discussion, surprise is all about production relative to expectations, and we're focusing solely on the positive side of things. Tomorrow, we'll explore the other end of the spectrum with each team's biggest disappointment of 2021.

Let's get to it!

 

AL East

Baltimore Orioles: CF Cedric Mullins

A .225/.290/.342 hitter with minus-0.3 WAR in 119 career games in the big leagues entering the year, Mullins was one of baseball's biggest breakout stars in 2021. With a 135 OPS+, 5.7 WAR and the first 30/30 season in Baltimore Orioles history, the 27-year-old now looks like a long-term building block.

     

Boston Red Sox: RHP Garrett Whitlock

Shoutout to free-agent signings Enrique Hernandez (4.9 WAR) and Hunter Renfroe (2.4 WAR), but no one expected a Rule 5 pick to be a key contributor. The fact that Whitlock was plucked from the rival Yankees farm system made his breakthrough performance that much sweeter. The 25-year-old had eight wins, two saves and 15 holds in 46 appearances, posting a 1.96 ERA, 1.11 WHIP and 9.9 K/9 in 73.1 innings.

     

New York Yankees: LHP Nestor Cortes Jr.

After spending the 2020 season with the Seattle Mariners, Cortes returned to the Yankees on a minor league deal. The 26-year-old was called up from Triple-A in May and he eventually found his way into the starting rotation at the end of July. The crafty southpaw used a fastball that averaged 90.7 mph and a wide array of offspeed stuff to post a 2.90 ERA, 1.08 WHIP and 103 strikeouts in 93 innings while helping to stabilize the starting staff down the stretch.

      

Tampa Bay Rays: C Mike Zunino

In 2019 and 2020, Zunino hit .161/.233/.323 with 13 home runs and a 50 OPS+ in 373 plate appearances, and the Rays declined a $4.5 million option last offseason. He ultimately found his way back to Tampa Bay on a one-year, $3 million deal that included a 2022 club option, and this time it's a lock to be exercised. The 30-year-old posted a 138 OPS+ with 33 home runs and 3.7 WAR in 109 games, earning an All-Star nod in the process. Fellow All-Star Andrew Kittredge deserves a mention here as well.

     

Toronto Blue Jays: LHP Robbie Ray

Ray showed enough down the stretch in 2020 to be worth a one-year, $8 million roll of the dice, but no one could have guessed he would be the AL Cy Young front-runner after he struggled to a 6.62 ERA with 45 walks in 51.2 innings a year ago. The 30-year-old led the AL in ERA (2.84), WHIP (1.05), strikeouts (248) and innings pitched (193.1), and a nine-figure payday likely awaits this winter.