"In my eyes, the best first baseman in the game right now defensively, and the best first baseman that's ever played behind me," said starter Kendall Graveman, who won his eighth game and benefitted from several strong plays in the field.
"I've never seen anybody better," catcher Stephen Vogt said. "Maybe there's some as good, but none better."
Alonso made several impressive plays Monday, including ranging into the Coliseum's expansive foul territory in the third to snare a pop fly from his brother in-law Manny Machado. Alonso noted "those are probably the plays I hate the most," considering the added challenge of avoiding the bullpen mound in foul ground.
He also made a diving stop on a ball hit by Pedro Alvarez in the fourth, diving to his right to snare a grounder before flipping to Graveman for an out.
The only person who didn't seem very impressed following the game may have been Alonso himself.
"That's what I expect out of myself," he said. "That's what I want to do every single night … That's why I'm there. That's why I put in the work. My teammates expect that out of me, to make every single play I can."
Alonso has made three errors at first base this season. His FanGraphs Ultimate Zone Rating per 150 games, which attempts to quantify how many runs a player saves per season on a 150-game scale, is -3.4 -- 16th out of 22 qualified first basemen in the league. And while Monday's display is a small sample size compared to his total body of work this season, the A's have raved about Alonso's reliability at first all year.
"I don't know about all these sabermetrics or whatever, all these runs saved," said Vogt, "but he better be up there. He's some kind of good over there at first base."
Melvin said it's unlikely second baseman Eric Sogard will play this year. He is recovering from left knee surgery in April. Sogard visited with Dr. James Andrews, who performed Sogard's surgery, on Monday. Melvin said Sogard is taking grounders and dry swings, but still can't run at 100 percent.
"It was a simple surgery, but the rehab was kind of lengthy," Melvin said. "There weren't any setbacks or anything like that."
Melvin said team doctors won't allow Sogard to return before he's 100 percent. With the Minor League season ending in about a month, a stint in either the Arizona Fall League or winter ball seems more likely for Sogard, who hasn't played this year.
"I doubt he'll be able to play here before the end of the season," Melvin said.
Two A's relievers are also in various stages of recovery. Sean Doolittle threw a 31-pitch bullpen session Tuesday, and Melvin said the team will determine soon whether he needs another bullpen session before facing live hitters as he returns from a strained right shoulder.
Melvin said Fernando Rodriguez, who is out with a right shoulder injury, is feeling better but is not yet playing catch. It's unclear if Rodriguez will return this season.
Mark Chiarelli is a reporter for MLB.com based in the Bay Area. This story was not subject to the approval of Major League Baseball or its clubs.