Robert Person, 2001
Full credit to guys like Robert Person, who were long shots to ever make the majors to begin with but ended up fashioning a career out of it.
He was a pretty unknown commodity when the Phillies pried him out of Toronto in 1999 for the hefty price of Paul Spoljaric, and the Phils decided to make him a rotation regular to see what he could offer. The results were promising, as Person went 10-5 with a 4.27 ERA with the team that year, locking down his rotation spot for the 2000 Phillies.
That season was so bad that it was fun, but Person more than did his part by going a very respectable 9-7 with a career-best 3.63 ERA. That didn't end up being his standout campaign, however, as he had some tricks up his sleeve for 2001. His first half was middling, but from July onward, Person went 9-2 with a 3.58 ERA to become the club's most dependable starter as they made a surprise run at a playoff berth. He ended the year with a 15-7 record and a 4.19 ERA. Person even cranked a pair of home runs at the plate in 2001, although his epic two-homer game actually came the following season.
Unfortunately for Person and the Phils, he couldn't build on his 2001 campaign, going just 4-5 during a 2002 season that was cut in half by injuries. He became a free agent at that point, signed with the Red Sox, appeared in seven games in 2003, and then never returned to the majors.