Danny Glover and James Roday (daemonstv.com)

Guest star Danny Glover played Mel Hornsby, longtime manager of Santa Barbara's local team, the Seabirds. When the Seabirds' hitting coach is found dead in his house with drugs in his system, Hornsby suspects murder. He hires Shawn and Gus to secretly investigate the coach's death. This is something Shawn, a longtime fan, revels in (he gets to go undercover as a coach) and Gus, true to character, hates (he's forced to be the mascot).

The episode's funniest scene comes early in the hour, when Shawn and Gus break into the dead hitting coach's house. With no regard for boundaries, Shawn eats the man's food and drinks from his team water bottle. Then, suddenly, Shawn's brain spins out of control; he starts thinking and acting at a super-fast rate, unable to do anything but focus. They later discover that the water bottle Shawn drank from was laced with amphetamine, which, at a high dosage, caused the coach's death. Playing Shawn on speed proves James Roday's impressive physical acting ability; he does frantic push-ups, juggles, plays a game of cards and quickly counts an entire bowl of chickpeas a la Rain Man, all in under 30 seconds.

The water bottle that killed the coach belongs to Izzy Jackson (Ken Luckey), the newest and most expensive member on the team. To prove that Izzy is the murderer, Shawn and Gus try to trick him into admitting to use performance-enhancing drugs. Izzy denies it, and when they test his urine, it comes back clean.

The next suspect on the table is Cal Eason (Michael Trucco from USA's Fairly Legal), Shawn's longtime Seabirds idol. Cal came back from the majors due to a knee injury. He was eager to go back to the big leagues as a first baseman, but Izzy was starting at that position and therefore in his way. Shawn assumed that Cal was trying to pin Izzy with drugs to take his spot, but the hitting coach accidentally drank Izzy's water instead.

They end up ruling out the Cal theory early on, but Shawn is in no rush to solve the case. He's enjoying his time as the fill-in hitting coach, bossing people around without a clue how to do so. To his frustration, everyone mistakes him for the towel boy, and he never gets a real role on the team. Gus, on the other hand, is praised for his "skills" at dancing as the mascot. When he's flailing on the ground itching from the costume's fleas, everyone cheers, thinking he's doing "the worm".

The case takes a major twist when Izzy, after a fight with Mel, is found dead. Everyone suspects Mel for the murder, but Shawn is the only one who believes he's innocent. After digging through some team records, he ends up being right and discovering the real killer: the Seabirds' general manager, Neil (Matt Kaminsky). He'd made a bad deal signing Izzy, because despite Izzy's popularity, he wasn't a good enough hitter to make it to the majors. In order to break the deal and keep the team from losing money, he tried to get Izzy caught with drugs... which ended up killing the hitting coach. Not knowing what else to do, he eventually killed Izzy.

"Dead Man's Curveball" was definitely one of the best of the season so far, but came nowhere close to topping Episode 2's fantastic "Last Night Gus". Maggie Lawson and Timothy Omundson were sadly out of the picture most of the episode, but there was a lot of great father-son chemistry between James Roday and Corbin Bernsen. One of their best scenes was during a police department softball game, when Henry, playing umpire, called his son out at home plate, and they erupt into a huge, over-the-top argument.

Next week: "Psych" goes from the baseball diamond to the mental hospital. In a spoof of "One Flew Over The Cuckoo's Nest", Shawn and Gus go undercover at a psychiatric ward. Molly Ringwald guest stars as a nurse, mirroring the "Cuckoo's Nest"'s antagonist, Nurse Ratched.

"Psych" airs Wednesdays at 10 PM on USA.

Reach writer Stephanie Case here.