Eli James (Jamie Kennedy) is a new character that was introduced in the first episode of season four.
During a building fire on the Rockland University campus[1], he dies but is brought back, causing him to have a near death experience. This unlocks an ability that allows him to hear ghosts, but doesn't allow him to see them like Melinda. At first he just believes he is losing his mind, but after hearing his deceased friend in ghost form he starts to accept his new ability. Throughout the fourth season, he adjusts to his newfound ability and starts helping Melinda cross ghosts over. Eli becomes a better person and a good friend to Melinda, Jim and Delia. Even during Jim's phase as amnesiac Sam Lucas, Eli was like a best friend to Jim, but his loyalty was to Melinda first which he made pretty clear to Jim when he wouldn't believe in Melinda's gift[2]. When Rick Payne leaves for his sabatical, Eli pretty much steps in as the goofy expert that Melinda turns to except that his expertise is in psychology in which he has a PhD. His knowledge of the human mind becomes a very useful tool in helping to cross ghosts over into the light, something Melinda trusts him to do on his own. Eli becomes quite adept at his new side job helping ghosts.