SAN FRANCISCO -- A special guest was on the field watching batting practice on Monday at AT&T Park.
Osiris Johnson, the Marlins' second-round pick on June 4 in the 2018 MLB Draft, and his parents were at the series opener against the Giants. Johnson has yet to sign with the Marlins, and he has a commitment to Cal State Fullerton.
Johnson, from Encinal (Calif.) High School, was the 53rd overall pick. The 17-year-old is the cousin of former All-Star shortstop Jimmy Rollins.
"It's pretty exciting," Johnson said of being in a big league setting. "I'm kind of used to it, being with Jimmy when I was younger."
Wearing a Marlns cap and a "Re2pect" hoodie, Johnson spoke at length with Marlins president of baseball operations Michael Hill, and was introduced to manager Don Mattingly.
"He seems really cool," Johnson said of Mattingly, noting he had to hurry along to get ready for the game.
Johnson made great strides in his senior season, batting .535 with six home runs and 24 RBIs in 26 games. What stood out to the Marlins' evaluators was Johnson's bat speed.
Before his final prep season, he worked with Rollins.
"I'm sure that had something to do with the vast improvements Osiris Johnson made from last summer to this spring, which enabled him to be in position for us to take him in the Draft," Marlins vice president of player development and scouting Gary Denbo said the first night of the Draft. "I think it's always good to have somebody in the family that's been through those types of experiences to advise a player. It's really important to have a support system for Minor League players that are coming through, because it's a tough game."
Asked what he gained from working with Rollins, Johnson said: "Just the discipline part of the game. Making sure I stayed disciplined."

The Marlins have already announced 16 Draft signings, including outfielder Connor Scott, who was taken 13th overall from Tampa (Fla.) Plant High School. They've yet to announce, but have reached agreement with catcher Will Banfield, taken 69th overall from Brookwood (Ga.) High School in the Competitive Balance Round B.
Worth noting:
•  Garrett Cooper played four innings in left field in a rehab assignment game for Class A Advanced Jupiter, going 2-for-2. Cooper is recovering from a right wrist contusion, and is expected to need several weeks to get back into playing shape. After a few games with the Hammerheads, he is expected to continue his rehab assignment at Triple-A New Orleans.

• Third baseman Martin Prado (left hamstring strain) is progressing in his recovery, and could return before the All-Star Break.