Walker went 2-for-4 with a solo home run in Wednesday's 3-1 win over Toronto.

Walker got the Astros on the board in the second inning, when he took Bowden Francis deep to left-center field for a solo homer. Walker seems to have a turned a corner as of late, and over his last five games he's gone 7-for-19 with four runs scored, two home runs and four RBI.

Aranda is out of the lineup for Wednesday's game against the Diamondbacks, Marc Topkin of the Tampa Bay Times reports.

Aranda has four homers and a 1.098 OPS through 21 games this season, but he will take a seat Wednesday with left-hander Eduardo Rodriguez set to toe the slab for Arizona. Curtis Mead will start at first base instead and bat fifth.

The Athletics selected Kurtz's contract from Triple-A Las Vegas, and he's starting at first base and batting seventh in his MLB debut against the Rangers on Wednesday.

Reports first surfaced Monday indicating that Kurtz was on the move to the big leagues, but the Athletics waited until they had a matchup Wednesday with a right-handed starting pitcher (Kumar Rocker) before making the 22-year-old's call-up official. Despite the brief delay in his promotion, the left-handed-hitting Kurtz is expected to be given the chance to play regularly against both right- and left-handed pitching as he begins his major-league career. In leagues where he's still available on the waiver wire, Kurtz is worthy of a look for teams in need of power production after he slashed an impressive .321/.384/.655 with seven home runs and seven doubles over 20 games with Las Vegas prior to his call-up.

Tellez is out of the lineup for Wednesday's game against the Red Sox.

Lefty Sean Newcomb will be on the bump for Boston, so the lefty-hitting Tellez will retreat to the bench Wednesday. Donovan Solano will start at first base in place of Tellez.

Mountcastle is out of the lineup for Wednesday's game against the Nationals.

The Orioles are deploying Jordan Westburg as their designated hitter Wednesday while he gets eased back into the lineup following a recent upper-body injury, and with Ryan O'Hearn picking up the start at first base, the team won't have a spot available for Mountcastle. The move to the bench comes after Mountcastle went 5-for-33 with a 1:9 BB:K over his last 10 games.

Walker went 3-for-3 with a double, an RBI and a run scored Tuesday against the Blue Jays.

Walker has been stuck in a season-long slump, but he's slowly shown signs of turning things around. His performance Tuesday marked his first multi-hit game since April 11 and only his fourth of the season. Across his last four games, Walker has homered, driven in three runs and scored three runs.

Dalbec went 1-for-2 with a double and a walk Tuesday against the Twins.

Dalbec was added to the roster Monday and made his first start of the season at third base while hitting eighth Tuesday. He was in the lineup to give Miguel Vargas a breather, so there doesn't appear to be a clear path to regular at-bats for Dalbec. However, if he can string together some hits, the White Sox may be inclined to find creative ways to get him into the lineup.

Casas went 1-for-3 with one walk and a three-run home run in Tuesday's 8-3 win over Seattle.

Casas extended the Red Sox's lead to four runs in the seventh inning, when he took Trent Thornton deep to center field for a three-run home run. It was Casas' second homer of the season, and he has a disappointing .519 OPS through 22 games and has just three hits in his last 25 at-bats.

Athletics general manager David Forst said Tuesday that Kurtz will not be platooned, Martin Gallegos of MLB.com reports.

The left-handed-hitting Kurtz has batted .296/.323/.482 versus lefties this season at Triple-A Las Vegas, and the Athletics want to give their top prospect a chance to be an everyday player. Kurtz will not play Tuesday against Rangers lefty Patrick Corbin, although that's more about giving him a chance to get acclimated in the majors. It's not clear whether the Athletics will officially add Kurtz to the roster Tuesday or wait until Wednesday. Kurtz is expected to serve as the Athletics' everyday first baseman, with some starts at designated hitter likely to be mixed in.

Athletics general manager David Forst said Tuesday that Soderstrom will see some playing time in left field and at designated hitter once first baseman Nick Kurtz is promoted from Triple-A Las Vegas on Wednesday, Martin Gallegos of MLB.com reports.

Soderstrom has never played a position other than first base and catcher during his time in professional ball, so he will be learning left field on the fly. Brent Rooker will also see increased reps in left field in addition to DH. Kurtz is likely to see some action at DH as well, but most of his playing time will likelly come at first base, where he is regarded as a superior defender to Soderstrom.