Guillen isn't saying Eovaldi will be the next Justin Verlander, but there are some traits.
For one, both throw in the upper 90s and have electrifying stuff.
"I remember one very, very good guy," Guillen said. "When Verlander was a baby, he was like this kid too. He was all over the place. He was a thrower. Then Justin began to throw strikes. He fixed his pitches. And look where he is right now."
Verlander, the Tigers' ace, is the reigning American League Cy Young Award winner and one of the most dominating starters in the Majors.
Eovaldi, obviously, has a long way to go. The rookie is 22, and he has deal with control issues. He's had his struggles, sporting a 4-12 record with a 4.29 ERA.
"I'm not saying I compare [Eovaldi] with him," Guillen said. "But the same kind of arm. I hope he ends up like him. I will compare him to Verlander early in his career. Hopefully he can reach that potential."
In his last two starts, the Marlins are seeing signs of what Eovaldi is capable of achieving. Both games were against the Braves, and he ended up settling for a no-decision each time.
On Tuesday, Eovaldi gave up two runs on four hits with a career-high eight strikeouts in six innings. He was in line for the win, but Freddie Freeman belted a two-run, walk-off homer in the ninth inning.
On Sept. 18 at Marlins Park, Eovaldi shut the Braves out for eight innings.
In the game, Miami let a three-run lead in the ninth inning slip away, but the Marlins won it, 4-3, in 10 innings.
"His stuff is electric," Braves manager Fredi Gonzalez said. "When we saw him in Miami, we had no chance. But he commanded every pitch. I think [Tuesday], he wasn't as good with the command. I think he's going to be good for a long, long, long time."