When Jon Matlack arrived in Arlington ahead of the 1978 season, he did so as part of one of the most complex, history-making blockbusters ever executed—the first four-team trade in major league history. Having already established himself as a three-time National League All-Star, a Rookie of the Year, and a pennant-winning co-ace with the New York Mets, the smooth-throwing left-hander brought an exceptional, top-tier pedigree to the Texas Rangers' pitching staff.

Although no longer at his peak of early-1970s National League dominance, Matlack quickly became a reliable, high-leverage asset for a Texas team striving to climb the competitive American League West. He adapted effortlessly to the intense summer heat at Arlington Stadium, using his excellent control, a sharp breaking ball, and strong pitching instincts to consistently keep batters guessing.

His early years with the team showcased reliable durability in the starting rotation. In his debut 1978 season, Matlack pitched 226.1 tough innings, recording 15 wins, 12 complete games, and 3 shutouts—just what the Rangers expected. He continued to perform well in 1979, with another 15 complete games and a solid 3.30 ERA, demonstrating that his move to the American League was smooth and successful.

As he entered his thirties and the Rangers began to reshuffle their pitching staff, Matlack showcased a remarkable, unheralded level of versatility. Over his final three summers in Texas, he masterfully alternated between the starting rotation and the bullpen. Whether he was taking the ball for a Sunday start or coming out of the bullpen as a late-inning fireman to preserve a slim lead, he executed his assignments with quiet, level-headed professionalism. His multi-dimensional efficiency peaked in 1980, when he split 34 appearances between starts and relief outings to log 10 wins and a tidy 3.68 ERA over 164.0 innings.

Matlack played three more seasons before retiring after the 1983 campaign.  With Texas, he posted a 43–45 record, a 3.42 ERA, and a 1.25 WHIP. He compiled 828.0 innings, striking out 493 batters.