From an ESPN article and there are several others from different publications:
"
As a second baseman, Eckstein worked his way through the Red Sox farm system. Two weeks into the 2000 season at Triple-A Pawtucket, attempts to "correct" his swing left him batting a mere .160. Eckstein took matters into his own hands; he apologetically defied authority, reinstated his swing and raised his average to .245.
But when the Red Sox needed a third baseman, Lou Merloni got the nod; Eckstein got waivers. Picked up by the Angels, however, Eckstein hit .285 as a rookie and is batting a steady .287 in his second season."
But something tells me Sprague was involved too.