Although a handful of candidates remain in line for the job with a platoon situation likely, it's sounding like it might come down to either Boog Powell or Dustin Fowler.
The two left-handed hitters have split time in center this spring. Powell batted .250 with three doubles and two RBIs in 19 games of the Cactus League while Fowler was hitting .227 with two doubles and four RBIs in 17 games.
Powell, who was acquired from Seattle in a trade last August, is the more experienced of the two. He played in 29 games with the A's last season and hit .321.
Fowler, acquired as part of the trade that sent Sonny Gray to the New York Yankees before the Trade Deadline last year, was in the Majors for only one game in 2017 before he ruptured his right patellar tendon.
"It's going to come down to the wire," Melvin said Monday before the A's played the Giants in the second game of the Bay Bridge Series at AT&T Park.
"We have guys that are playing really well. We feel great about Boog. We feel great about Fowler. Both are good players."
Jake Smolinski, who is batting .289 with four home runs and 13 RBIs this spring, is the leading contender to be the right-handed part of the platoon situation in center. Mark Canha is also getting a look.
"It's going to be a difficult decision at the end," Melvin said.
• Right-hander Trevor Cahill, who was signed on March 19 after the A's placed Jharel Cotton on the 60-day disabled list, will begin the season in the Minors and will make a handful of starts there before the team decides what to do.
"He'll pitch two to three innings [Tuesday] then probably have a couple games in development to get himself ready, back to start a Major League game again," Melvin said. "At this point, he looks to be the depth."
Cahill won 40 games in three seasons with Oakland and was an All-Star in 2010. Melvin noted that in his first game as manager of the A's in 2011, Cahill was the starting pitcher.
"Now, it's come full circle for him coming back," Melvin said. "It's one of the reasons we signed him is the injuries we've had. He looked good."
• Former A's closer Santiago Casilla has recovered from the shoulder issue that sidelined him for nearly two weeks in the spring, and Melvin expects the 37-year-old to be a fixture in Oakland's bullpen.
"You do the math, it's a good chance he's going to be with us," Melvin said. "He understands where he is as far as his role. Maybe not the same role he's had in years past but a great resource for the younger guys, too. I'm glad he's over the soreness he's had the last couple of days. I know he feels great right now."
The A's finish the exhibition season Tuesday at AT&T Park before making preparations for Opening Day. Right-hander Andrew Triggs will pitch for Oakland in the finale of the three-game Bay Bridge Series. The game can be seen for free on MLB.TV or heard on Gameday Audio.
Michael Wagaman is a contributor to MLB.com based in the Bay Area.