"I told him to go to Roy Rivas to eat a little bit, to fill him," said Guillen with a laugh. "You know who Roy Rivas is? The guy who cooked for the Chicago White Sox for the last 40 years."
Calling Sale svelte is as much of an understatement as calling the Chicago Blackhawks recent Stanley Cup championship a somewhat nice moment for the city. Although putting on weight has been an issue throughout Sale's career, it certainly hasn't translated into trouble on the field.
The 21-year-old junior finished with an 11-0 record and 2.01 ERA in 17 games this past season for Florida Gulf Coast University. He fanned 146 and walked just 14 for the Eagles, ranking second among all Division I pitchers in strikeouts.
Sale was projected as one of the top pitchers in the Draft, but dropped to the White Sox at No. 13 over perceived signability issues. Those issues didn't seem to linger into contractual negotiations, as Sale signed a Minor League deal with a bonus of $1.656 million.
Basically, getting his professional career started was of greater importance to Sale then haggling over a larger bonus.
"At first we were trying to negotiate," said Sale, holding his first press conference in the U.S. Cellular Field home dugout prior to Tuesday's game, in front of his father and fiancee. "The most important thing is playing baseball. No one gets better figuring out a contract. I like to play and I want to play.
"We were ready. Both of us thought it was a good deal and were ready to get this ship sailing."
That ship might sail to the Major Leagues before Sale's first professional season is complete. Sale will begin at Class A Winston-Salem, where he will work out of the bullpen under the watchful eye of pitching coach Bobby Thigpen, quite possibly the greatest reliever in White Sox history.
If Sale proves himself capable of handling the role, he will get promoted up the system's ladder. The ultimate target is working behind Matt Thornton as another left-handed relief option, with general manager Ken Williams speaking highly of Sale's polish and talent.
"He's a left-handed pitcher with a plus arm and a power changeup," Williams said. "Mark Buehrle has what we call, we grade on a 20 to 80 scale, and Buehrle has a 65 or 70 changeup when he throws good and so does John Danks. This guy starts his career with a 70 changeup, and sometimes plus.
"Right-handers are going to have to take notice of that. When he gets on top, he comes from a little different arm slot, so he's going to have to work to stay on top of his breaking ball, and when he does, it's a darn good, plus Major League pitch.
"What you worry about with young players is command. Well, he walked 14 guys in 100-plus innings and showed us that command to both sides of the plate. What you are developing in the Minor Leagues is that touch and feel for your fastball location and your secondary pitches and if he shows that he's capable of doing that, certainly not on a starting basis, but if you look to him to begin his career as a reliever and then graduate into that starting role, as he gets more experience and a little more weight and strength.
"You can start to look at the rotation possibilities," Williams said. "But early on, if he can handle the relief role and show he's ready, then you can look to put him into the equation sooner rather than later."
As far as Sale's concerned, he's ready to handle any job presented by the White Sox.
"Whatever they want me to do, I'm going to do," Sale said. "I just want the opportunity to pitch. Pitching is pitching. You still got to get outs and you still have to produce. It won't be anything different."
Tuesday was a surreal experience for Sale, who passed his physical and then had a sort of "Is this really happening?" experience as he walked around the clubhouse and met Buehrle, Paul Konerko and other well-known White Sox players. Sale admitted the only thing he knew about the franchise was that it's based in Chicago, but White Sox fans might soon be learning about their skinny top pick.
Listed at 6-foot-6, 185 pounds, a smiling Sale first balked when asked how much he really weighed. Before the interview came to a close, Sale came clean and said he checked in at 168 pounds at Tuesday's weigh-in.
"Gaining weight is gaining weight, and it's not my main priority," Sale said. "You can get outs if you are 400 pounds or 168 pounds. So, if that's one of the things we need to work on, I will work on it."
"Nobody gets fired for being too skinny," Guillen said. "When you gain some pounds, the first excuse they tell you, they don't tell you you're bad, they tell you you're getting older, you're getting fat, you can't move anymore. I told him don't worry about it when people say you look like a pencil."
Scott Merkin is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.