It was a downgrade in his nickname, though, not for his chances to make the team or even earn the starting second base job.
"He's not the missile anymore," said Guillen to a group of reporters in Peoria, Ariz., now referring to Ramirez as the 'Cuban B.B. Gun.'
This moniker alteration came following Ramirez's three-strikeout performance on Sunday at home against the Royals. But Guillen refuses to read too much into the rookie's brief struggles covering the strike zone. In fact, he pointed to Ramirez's line-drive single in the ninth on Sunday as a small example of his ability to bounce back from adversity.
Guillen originally had planned to finalize the roster on Tuesday, following a meeting with general manager Ken Williams, assistant general manager Rick Hahn and their respective staffs. But the closest comment to a certainty Guillen could come up with on Monday is that the starting second baseman would be named at some point before or after Tuesday's game at Hi Corbett Field.
Pablo Ozuna already has been established as the second-base starter on Opening Day, bringing with him his .300 career average against Cleveland's C.C. Sabathia.
"Any time he uses me, I'll be ready to try to help the team win a game," said Ozuna, who started in left field against Sabathia on Opening Day, 2007.
Even with this Opening Day honor, Ozuna will be used in more of an infield utility role, ruling him out as the everyday second baseman. In reality, both Juan Uribe and Ramirez could provide this same sort of versatility, with Ramirez also able to play center, as he proved once again on Monday against the Mariners.
Figuring out the second base starter will be one of the questions to be answered by the White Sox brain trust, which also has to decide between Brian Anderson and Carlos Quentin for the final outfield slot and Nick Masset and Ehren Wassermann for relief spot No. 7.
Ramirez is not in jeopardy of missing the active roster, and Sunday's struggles certainly didn't dampen Guillen's enthusiasm for this explosive young player.
"We look around at who had the worst Spring Training and it's not Ramirez. I like what I see," Guillen said. "The decisions this year aren't going to be easy ones. We might have to see a couple players a couple more days.
"If we do that Tuesday, good. If not, we have to wait. My hope is that when we take the plane from Tucson [Friday], it's the club we'll use during the season."
Scott Merkin is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.