​Heading into the second half of the season, the Athletics, at 41-55, have dug themselves a hole. They are eight games back in the AL West, and 6.5 back for the final AL Wild Card spot, making any climb towards the postseason a difficult one.To begin that climb, the A’s have made some roster moves. The biggest one is that the club has designated Aaron Civale for assignment, a move we floated yesterday as a possibility in our trade candidates piece. The club has also optioned right-hander Mason Barnett, catcher Brian Serven, and first baseman Joey Meneses.AdvertisementAdvertisementAdvertisementThe A’s have only announced three corresponding roster moves, to go with those four departures. The fourth player will be No. 7 prospect Tommy White.The three that are definitely headed to Sacramento are left-hander Brady Basso, right-hander Yunior Tur, and infielder Donovan Walton, whom they claimed off waivers a couple of days ago.This is a similar move to the one the team made in May of last season, when they optioned JJ Bleday, called up Denzel Clarke and Willie MacIver, and DFA’d Seth Brown, among other moves.So how does the new roster fit together?One piece we were planning to write (and still may) during the break is that Jacob Lopez needs to be added back into the starting rotation. He was called up on July 7 and immediately threw 63 pitches against the Detroit Tigers in the game J.T. Ginn left early due to illness.AdvertisementAdvertisementAdvertisementJust three days later, Lopez was back on the mound to serve as the opener ahead of Civale, and he went 1 ⅔ innings without giving up a hit. A’s manager Mark Kotsay was impressed with that performance, really emphasizing that he thought Lopez’s outing was “great.”The fact that Lopez and Civale both pitched in the same game means they’re lined up for the same schedule at this point, so replacing Civale with Lopez would be the easiest route to fill that spot in the rotation.When Barnett came up and carved out a bullpen role for himself in Las Vegas back in June, he was firing on all cylinders, posting a 1.35 ERA across 13 ⅓ innings that month. The league has figured him out a bit more recently, as the righty has posted a 13.50 ERA across six July innings with a 2.33 WHIP.In three of his four outings this month, Barnett has allowed multiple runs. In that same span, he’s given up nine hits — four home runs — and walked five while striking out just two. This option will serve as a refresh for Barnett.AdvertisementAdvertisementAdvertisementYunior Tur will be making his MLB debut when he takes the mound for the A’s. The 26-year-old holds a 4.41 ERA across 51 innings (27 appearances, five starts) with a 1.31 WHIP. He’s also allowed just four home runs.The A’s offense has been struggling just as badly as the pitching staff of late, and with both Nick Kurtz and Zack Gelof on the IL, along with DH Brent Rooker out for the season, bringing up White is the quickest way to infuse some energy into this group.N