Another day, another trade on the South Side.

As part of the White Sox’s effort to continue their swift rebuild plans, the club moved yet another piece on Thursday morning in reliever Dan Jennings. He was sent to the Tampa Bay Rays for OF Casey Gillaspie, brother of former White Sox third baseman, Conor. Gillaspie is a switch-hitting first baseman who was the Tampa Bay Rays No. 10 prospect according to MLB.com. He has hit .227 with 15 doubles, nine home runs and 44 RBIs in Triple-A Durham this season.

Gillaspie is on the DL after breaking his big toe on Tuesday and will be placed on the DL by Charlotte. The injury should only sideline Gillespie one or two weeks.

With this move, Jennings became the fourth reliever traded by the White Sox in just eight days.

“You know that term ‘sellers’ is thrown around a lot,” Jennings said before Wednesday’s game. “And you never want to think of it that way, because whoever is here whoever that may be, is going to do everything in their power to win every game despite the situation.”

Jennings certainly had some noticeable trepidation in his voice as he spoke to the media less than 24 hours prior to the trade and for good reason. He was next in the line of falling dominos of this aggressive rebuild process.

Jake Petricka, the only reliever left who was on the White Sox Opening Day roster, spoke on the situation.

“Up here, no,“ Petricka said when asked if he’d ever seen such quick bullpen turnaround. “In the minors, yes. I mean there goes those phases when the new draftees come in and faces turnover but, it’s a little different up here. But again it’s a good thing and a bad thing.”

Unlike Todd Frazier, Tommy Kahnle, and David Robertson, Jennings was not afforded final words with his teammates before he departed to his new team. “No, that was through text message,” Petricka said of his goodbyes to Jennings. “It’s one of those things, like I said, you wait for that call and then you get it and you’re gone. Unless you’re in the locker room like Todd and Tommy and D-Rob were, we don’t really get a chance to say goodbye to them, which makes it kind of hard but it’s the nature of the business.”

Jennings pitched 44.1 innings this season with the White Sox to the tune of a 2.45 ERA and struggled with the long ball this season; he gave up six home runs and held a 24 percent HR/FB rate. Guaranteed Rate Field being a friendly hitters ballpark likely contributed to the Jennings’ struggle with fly balls leaving the yard.

Despite the somber atmosphere surrounding the clubhouse after losing two games in a row to the Cubs, as well as a handful of teammates, the mood was anything but somber for new reliever Aaron Bummer. Bummer was called up to the majors from Charlotte for the first time in his career to take Jennings’ place in the bullpen.

“I was getting food last night in Charlotte and Steve McCatty came over and grabbed me, took me out of the food line into our manager’s office,” Bummer said of when he was informed of the call up. “He told me what was happening, and I just sat there with a dumbfounded smile on my face, not really knowing what to expect, just spitting out gibberish. It’s a moment I’ll never forget. I thank the White Sox and everybody for this opportunity.”

Bummer, wide eyed and bushy-tailed, stated how exciting this moment was for him and his family.

“My parents were sleeping and woke up right away and they bought a plane ticket for tonight,” Bummer said. “The next person I called was my girlfriend and she started bawling immediately. So it was a whole bundle of emotions for all of us. It was an awesome experience.”

Bummer, who has put together a 2.84 ERA between Double-A Birmingham and Triple-A Charlotte, said that Jennings was a mentor for him during the time that they spent together in Spring Training.

“One of the guys who helped me out a lot was Dan Jennings,” Bummer said before Thursday’s game. “It’s kind of bittersweet to know it was a give and take. He kind of took me under his wing a little bit and learned the routine. He was a real big help for me and it’s one of those things I take a lot of pride in that routine.”

Making your Major League debut despite the state of the club you’re coming to is still an experience, and it isn’t short of a small case of the nerves for Bummer. “The sooner we get to this debut, I’ll be a little bit more at ease and things will be a little bit easier.” Bummer said.

While the White Sox rebuild is beginning to hit it’s stride as the trade deadline approaches, today was anything but a “bummer” for the White Sox new young reliever.