Ask anyone in Oakland's clubhouse about the 24-year-old Smith, and they all rave about his high baseball IQ.
Rookie Dana Eveland, Smith's teammate at Triple-A Tucson last season, calls the Louisiana native "a genius" and a classic lefty who is "very crafty."
"He's the guy you look at and wonder how he gets guys out," Eveland said. "He puts a lot of effort into looking at the hitters and seeing who can do what, what to throw to whoever."
Smith had his contract purchased from Triple-A Sacramento on Wednesday, just in time for him to make his Major League debut against the Blue Jays.
With Smith added to the 40-man roster, the A's were forced to designate first baseman Dan Johnson for assignment, likely ending his career with the team that drafted him out of the University of Nebraska in 2001.
"It's difficult to do, but Dan will get another opportunity and I'm sure he'll take advantage of it," A's manager Bob Geren said.
Oakland needed Smith because righty Justin Duchscherer is on the 15-day disabled list with a strained right biceps.
Catcher Kurt Suzuki knows Smith from 2006, when they played together on the U.S. team that qualified for the Beijing Olympics. Like Eveland, Suzuki came away impressed with the way Smith uses his head to keep opposing hitters off balance.
"I got a little idea of what kind of person he is," Suzuki said. "That guy is smart, he's a pitcher. He studies and he goes about his business. He works his butt off every day he's out there. For me to be able to catch him is going to be cool."
One of six players who came over from Arizona in the offseason trade that sent Dan Haren to the Diamondbacks, Smith combined to go 9-5 with a 3.54 ERA in 22 games at Double-A and Triple-A last season.
Smith lost the only start he made for the Sacramento River Cats this April, giving up two runs on six hits in six innings, walking one and striking out four.
Geren had never met Smith before he showed up in Toronto, but had read about him and watched him give online interviews.
"He's been impressive in every way, shape and form," Geren said. "He's an intelligent guy. He's got good control on the mound, a good game plan. He's a competitor."
Johnson's departure was expected, given that rookie Daric Barton has a lock on the first-base job. With Mike Sweeney also on the Oakland roster, opportunities for Johnson were few and far between; he was hitless in his only at-bat this season.
Johnson enjoyed a solid rookie season with the A's in 2005, batting .275 with 15 homers and 58 RBIs. But in 2006, he ended up back in the Minors in July after his numbers slipped across the board.
The 28-year-old Johnson put a hip injury behind him and set career highs with 18 homers and 62 RBIs last season, but his batting average slipped to .236.
John Arthur is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.