Athletics Opening Day countdown: Mark Mulder is best No. 20 in A’s history

September 27, 2015, Oakland, CA, USA, Athletics former starting pitcher Mark Mulder accepts gifts from the Athletics before the game at O.co Coliseum alongside San Francisco Giants starting pitcher Tim Hudson (17) and Athletics starting pitcher Barry Zito (75). Mandatory Credit: Ed Szczepanski-Imagn Images

20 days remain until Athletics Opening Day at the Toronto Blue Jays on March 27, 2026. With Las Vegas on the horizon, this daily countdown tracks the best A’s players by jersey number.

Today, March 7, 2026, the number is 20.

Mark Mulder, No. 20

Mark Mulder is the best Athletics player to wear No. 20 because he delivered real prime years for the team. He was a rotation anchor during a winning window and he did it for multiple seasons.

Mulder pitched for the A’s from 2000-04. Over that five-year run, he became a two-time All-Star and one of the faces of the staff.

Why Mulder gets No. 20

Mulder gets No. 20 because his Athletics workload and results stand out in this jersey group. He went 81-42 with a 3.92 ERA in 150 starts for Oakland.

He also logged 1,003 innings as an Athletic and posted a 114 ERA+. That mix of durability and effectiveness is the separator for this number.

Career start and background

Mulder was born Aug. 5, 1977, in South Holland, Ill. He went to Thornwood High School, then played at Michigan State.

The Oakland Athletics drafted him in the first round, No. 2 overall, in 1998. He debuted with the Athletics on April 18, 2000.

Other notable No. 20s

• Josh Donaldson, 2012-2014
• Mark Canha, 2015-2021
• Huston Street, 2005-2008
• Zack Gelof, 2023-2025

Career check

Mulder did not have the longest career arc, but his A’s stretch was the most meaningful at this number. For No. 20, the 81 wins and five-year run make him the pick.

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Dice City Sports editor Mark Hebert covers the Vegas Golden Knights, Las Vegas Raiders, Athletics, and UNLV baseball and softball. He has 24 years of journalism experience, is also a senior reporter at Exhibit City News, and previously covered the Dallas Stars and Texas Rangers. Follow him on X or connect on LinkedIn.