I remember when the Seattle Mariners traded Mike Hampton to the Astros. OK, I don't remember the exact date, but Baseball-Reference tells me it was Dec. 10, 1993. What I do recall is that the trade seemed liked a head scratcher at the time. Hampton was a young (21) left hand pitcher who had only pitched 17 innings at a very young age (20) for the Seattle major league team, resulting in a 9.53 ERA. Hampton had an unremarkable minor league career, and he was unranked as a prospect.
The Astros traded Eric Anthony, a young outfielder whom Astros' fans viewed as the franchise's next big slugger. Eric Anthony had been ranked as baseball's No. 9 prospect by Baseball America before he reached the majors, and he had a career .919 OPS in AAA with monstrous HR power. Anthony was 25 years old, and had played several partial seasons with the Astros. He had not yet established himself as a major leaguer, but his 24 HRs over the 1992 and 1993 season made it appear that he was ready to do so.
I had this nagging feeling that the trade would come back to haunt the Astros. The only positive note was that the Astros' beat writer said that the Astros' scouts liked Hampton quite a bit. At the time, a casual fan might have assumed that Hampton's future would be as a left handed relief specialist. I was wrong about the trade. Hampton would become one of the finest starting pitchers in Astros history. Anthony? Well, he never became more than a back up outfielder.
In retrospect, the Astros and Mariners attempted an exchange of untapped potential. And the Astros took the younger player and won. And obviously what the Astros scouts and front office saw in Hampton was a left hand pitcher with a powerful sinker pitch that would produce ground out after ground out. Hampton would carry a low K rate (5.5 career average) throughout his career, which may be why he was undervalued as a young player. But the groundballs were the story.
Initially, the Astros used Hampton as a left handed reliever, where he compiled a respectable 3.70 ERA as a 21 year old in 1994. In 1995, the Astros converted him to a starter and he produced an even better 3.35 ERA in 150 innings. In 1997, after Larry Dierker was named manager, Hampton began to emerge as a young work horse starting pitcher, leading the Astros into the playoffs by pitching 223 innings. In 1998, Hampton had an ERA+ of 123, and was joined by another ex-Mariners' pitcher, Randy Johnson, on the Astros highest win (102) team. In 1999, Johnson was gone, and Hampton had a chance to shine as the ace of the staff. And he did. He compiled a 22-4 win-loss season, with an ERA+ of 142 in 217 innings. B-Ref's advanced stats tell us he produced an impressive 6.6 WAR. Unfortunately, the Astros lost to the Braves in the playoffs.
With the Astros failing to succeed in the playoffs for three straight years, and Hampton one year away from free agency, the Astros traded Hampton to the New York Mets for Octavio Dotel and Roger Cedeno before the 2000 season. Hampton led the Mets to a World Series that year, and then bolted to the Rockies for the 8th highest pitcher free agent contract in history (8 years, $121 million in 2001). Unfortunately for Hampton, he was pitching at Coors Field during its heyday as a hitter's park. His ERA suffered, not surprisingly, and after a series of trades, he ended up in Atlanta. Hampton's career with the Braves was plagued by a series of injuries and surgeries which left him with the injury prone reputation. Hampton returned to the Astros as a free agent in 2009, but arm injuries continued to hamper him, and eventually ended his season. A young prospect, Bud Norris, replaced Hampton in the Astros rotation. (See, the story connects us to the current team..and the wheel goes round and round.)
A couple of notable points about Hampton's career. First, he has considerable playoff experience, pitching in 11 playoff games (10 as a starter) with an average ERA of 3.74. Second, Hampton can be thankful he was traded to the National League by the Mariners, because he became one of the best hitting pitchers in the league. Hampton compiled 8.3 WAR as a batter. His career slash line: .246, .296, .356, .650. During his time in Colorado, he hit .315 and produced an .881 OPS.
The Astros and Mariners have had a number of notable trades. Some helped the Mariners more, and others were fairly even. But this one went in the Astros' favor.