Jordan is a Julliard educated keyboardist who has been producing music since the early 80s. His discography can be found on JR.com.
When DT first asked him to join the band (in 1994, after Kevin's departure), he instead decided to join The Dregs, who had asked him to join them on tour at almost the same time DT were talking to him.
It was with the Dregs that he formed RMP with Rod Morgenstein, a band that later opened for Dream Theater, and when MP was putting together LTE Jordan was the keyboardist chosen for the project. Working with Jordan prompted Mike and John to ask him once more to join the band, and since he'd finished with the Dregs he accepted their offer.
Is there an online source stating this?