Baker had to compete with Kevin Slowey for the starting rotation in 2011, but he won the competition and entered the season as the Twins' No. 5 starter. He threw seven shutout innings on April 21 in a 3–1 victory over the Baltimore Orioles. He threw a complete game on June 11, allowing one run and striking out seven in an 8–1 victory over the Rangers. One week later, he threw eight shutout innings and had 10 strikeouts in a 1–0 victory over the San Diego Padres. Baker had a strong season before missing time with injuries. His ERA at the end of July was 2.86, and he made two starts in August before spending much of the rest of the season on the disabled list with an injured elbow. He finished the season with an 8-6 record and a 3.14 ERA. Baker was the Twins only starting pitcher to have a winning record in 2011, and he led the team in ERA, strikeouts (123), and WHIP (1.17).