Red Sox director of player development Brian Abraham recently said the organization is looking for Mayer to develop an increased walk rate, a narrowed strike zone and to see more left-handed pitching, Jen McCaffrey of The Athletic reports.
Abraham responded to the question of what Mayer has left to prove at Double-A Portland. The prospect has shown improvement in the first two areas, but Abraham acknowledged it's harder to evaluate his performance against left-handed pitching because there aren't as many in the minors. He also wants to see the shortstop increase his range defensively to the arm side and make those plays in the hole. "So while it might be smaller areas of improvement, I think those areas are going to allow him to be great, not just good," Abraham said. "Those things don't happen overnight." Mayer, who is batting .307/.371/.479 over 299 plate appearances, should see Triple-A Worcester in the second half.