Cliff Pennington, a switch-hitting infielder, began his Major League Baseball career with the Oakland Athletics. Drafted by the Athletics in the first round of the 2005 MLB Draft, Pennington made his debut with the team in 2008. Known for his defensive skills, he primarily played shortstop but also demonstrated the ability to cover second and third base when needed.

During his time with the Athletics, Pennington became a regular fixture in the infield. His defensive prowess was complemented by a steady, if not spectacular, offensive performance. In 2009, he secured the starting shortstop position and maintained it through the 2012 season. Pennington's speed on the bases was an asset, and he contributed to the team's dynamic with his ability to steal bases and score runs.

In 2012, Pennington was part of a trade that sent him to the Arizona Diamondbacks. His tenure with the Diamondbacks saw him continue to provide reliable defense and occasional offensive bursts. While with Arizona, he played multiple infield positions, showcasing his adaptability and team-first mentality.

Pennington's journey continued in 2015 when he was traded to the Toronto Blue Jays. Joining the Blue Jays during their playoff push, he added depth to their infield and appeared in the postseason for the first time in his career. His experience and steady glove were valuable assets during the Blue Jays' run to the American League Championship Series.

Following his stint in Toronto, Pennington signed with the Los Angeles Angels in 2016. Over two seasons with the Angels, he continued to be a dependable utility infielder, providing leadership and experience to a young team. His ability to play multiple positions allowed the Angels flexibility in their lineup and defensive arrangements.

In 2018, Pennington signed a minor league contract with the Cincinnati Reds, eventually making the major league roster. His time with the Reds was brief, and he was released later that year. Despite this, Pennington's career was marked by his consistent defensive skills and his role as a reliable team player across several MLB teams.