Colon was picked up by the Twins after the 44-year-old was released by the Atlanta Braves. The former American League Cy Young Award winner made one start with Triple-A Rochester, allowing four earned runs on as many hits in 3 2/3 innings against Lehigh Valley.
Colon struggled to a 2-8 mark with an 8.14 ERA in 13 starts for the Braves before being designated for assignment. He fared significantly better in 2016 with the New York Mets, posting a 15-8 mark with a 3.43 ERA.
A 20-year veteran, Colon owns a 235-170 record with a 4.02 ERA and 2,407 strikeouts over 522 career outings (513 starts).
Colon spent the first five-plus seasons of his career with the Cleveland Indians from 1997 to 2002 before going on to pitch for the Montreal Expos, Chicago White Sox, Anaheim/Los Angeles Angels, Boston Red Sox, Chicago White Sox, New York Yankees, Oakland Athletics, Mets and Braves.
His Cy Young season came with the Angels in 2005, winning a career-high 21 games opposite eight losses and posting a 3.48 ERA and 157 strikeouts in 33 starts.
Mauer, who had been sidelined since July 7 with a strained lower back, was expected to bat third in the lineup against the Houston Astros on Saturday. The 34-year-old is batting .286 with five homers and 34 RBIs in 75 games this season.
Buxton exited Friday's 10-5 loss to the Astros in the sixth inning with left groin soreness. The 23-year-old is hitting .218 with five homers and 16 RBIs in 84 games this season.