Don’t get me wrong, at the time this wasn’t a terrible deal. Only in retrospect can we see how much the Mets lost.
Outfielder Mike Cameron, he of great defense, good pop and even better speed, joined the Mets in 2004 and hit 30 home runs that season. In 2005, he was on pace for one of the best years of his career, hitting 12 home runs with 39 RBI and an elevated batting average through 79 games.
Partway through the year, however, he was involved in a terrible outfield collision with Carlos Beltran, forcing him to miss the rest of the season. It was a matter of two center fielders trying for the ball at the same time—Cameron had shifted to right field to accommodate the newly arrived Beltran, but he was a center fielder by trade.
In Cameron, the Mets had damaged goods who might or might not fully recover and a guy who was forced to play out of his natural position. Trading him, and his pretty large contract, seemed like a good idea.
On November 18, 2005, he was sent to the San Diego Padres for outfielder Xavier Nady.
Nady spent less than a full season in New York, hitting .264 with 14 home runs and 40 RBI in 75 games before himself being sent to the Pirates. Granted, he was a big reason the Mets got off to a hot start in 2006—they were 46-29 in games he played—but the brevity of his stay negated much of the impact he had on the club.
Upon leaving the Mets, Cameron averaged 23 home runs, 75 RBI, 81 runs scored and 17 stolen bases per year from 2006 to 2009. He was superior to Nady on defense, quicker on the base paths and possessed greater power. Nady, never a slugger, averaged only 10 home runs and 42 RBI per season from 2007 to 2012.
The Mets traded Cameron, a former All Star centerfielder, for Nady, a marginal starting outfielder, at best. At the time, it seemed like it made sense. But the power of hindsight suggests it didn’t.
Alex's Baseball Blog 