OAKLAND, Calif. — After throwing off a mound for the first time since going on the disabled list with a sprained right ankle, Orioles right-hander Ubaldo Jimenez could pitch a minor league rehabilitation game by the middle of next week, Orioles manager Buck Showalter said Friday.

Jimenez tested his ankle with a bullpen session during the Orioles’ post-All-Star-break workout in Oakland on Thursday and was pleased with the progress of his recovery. He will throw another bullpen session Sunday.

Showalter said Jimenez appeared tentative throwing on flat ground before the break, but Jimenez appeared to have power back in the ankle Thursday.

Thursday’s session “was better,” Showalter said. “The only thing left is throwing from the stretch. I’m hoping if that goes real well Sunday, he can go out and pitch. That’s what we’re hoping for on Sunday.”

If there are no problems Sunday, Jimenez likely would join one of the Orioles’ minor league affiliates for a rehab assignment start, most likely on Wednesday, Showalter said.

Jimenez is eligible to come off the disabled list Wednesday, but because he hasn’t pitched since the second game of a doubleheader in Boston on July 5, he will need to make at least one rehab start.

If he were to make just one rehab start, Jimenez would be in line to return when the Orioles return from their three-city, 10-game, West Coast road trip for a makeup road game against the Washington Nationals on Aug. 4.

Jimenez’s return would give the Orioles six starting pitchers, but Showalter said he’s excited to see whether Jimenez can duplicate last season’s second-half success with Cleveland. Jimenez had a 1.82 ERA in 13 second-half starts for the Indians in 2013.

Machado looking beyond booing

The hometown fans in Oakland apparently have not forgotten about Orioles third baseman Manny Machado’s bat toss and confrontation with Athletics third baseman Josh Donaldson last month at Camden Yards.

When Machado’s name was announced during pregame player introductions, Machado received an overwhelming chorus of boos.

“On our side, it is" forgotten, Machado said before the game. “I’ve served my suspension. I’ve done what I’ve needed to do. Now it’s time to play baseball. Baseball is a game where you forget about the past, at-bats by at-bats, pitch by pitch, so I’m just going to try to put it behind us and continue forward and hopefully see each other down the line.”

Asked how he would handle being booed, Machado said he would take any response in stride.

“Take it how it is,” Machado said. “It’s all a part of the consequences. It’s a part of the game. I can’t control anything [like that]. What I can control is going out there and putting the uniform on every day and do the best I can that do. I’ll take it in and take it how it is. It is how it is.”

Machado entered Friday’s game having reached base in 16 straight games, tying his career high. He is hitting .410/.455/.721 over that span. Over his past 36 games, Machado has raised his batting average 60 points, from .210 to .270.

“I’m looking forward to starting the second half,” Machado said. “It’s coming around. My body is finally feeling like it’s there on a constant basis, which is the important part. Hopefully I can continue this through the second half.”

Orioles wrap up signing draft class

The Orioles signed California high school right-hander Brandon Koch, their 33rd-round pick, just before Friday’s deadline to agree to terms with players selected in this year’s first-year player draft.

The club signed 31 of its 38 draft picks this season, including its first 16 selections. Twenty of the signed draft picks were pitchers.

The most notable unsigned player was college right-hander Brandon Bonilla, the team’s 25th-round pick, who is the son of former Oriole Bobby Bonilla. Brandon Bonilla did not pitch last season because he was academically ineligible.

Pitching coach to miss time

Orioles pitching coach Dave Wallace is scheduled to be away from the team Aug. 1-2 to attend his daughter’s graduation. Showalter said he’s expecting pitching rehab coordinator Scott McGregor to fill in as interim pitching coach.

“I was talking to Dave,” Showalter said. “We haven’t come to grips with finalizing it. [Bullpen coach] Dom [Chiti] is so good with what he does down there, I’ll probably leave him alone. Dave thought that would be a good idea. Scott has done so many things for us. He can handle anything."

Around the horn

Right-hander Chris Tillman will start Wednesday's series finale in Anaheim. Bud Norris is starting Monday and Miguel Gonzalez on Tuesday. ... In 33 games since June 9, the Orioles' rotation has posted a 3.18 ERA, lowering its season-long ERA from 4.61 to 4.09. … Since June 1, the Orioles have hit a majors-leading 60 homers, 16 more than the second-place Houston Astros and Detroit Tigers (44). … Right-hander Jon Keller was promoted to High-A Frederick from Low-A Delmarva on Friday. Keller, the club’s 22nd-round draft pick out of Tampa in 2013, was 3-0 with a 1.59 ERA and had five saves in 24 relief appearances for the Shorebirds. ... Showalter singled out fast-moving minor leaguer Mike Yastrzremski, who was 4-for-5 in his first game at Double-A Bowie on Thursday. Yastrzemski, who already has moved up two levels this season, hit his 13th triple of the season. “He’s got my attention,” Showalter said.

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