In completing their sweep of the Orioles on Sunday, the Rangers got a complete-game shutout from Derek Holland in just his fourth start since returning from the disabled list. And there’s a message in that outcome, something that you should keep in mind about this team as it heads down the stretch: These are not April’s Rangers, or July’s. This is a team with the talent to beat anybody in a short series.

That’s worth noting because even after Sunday’s shutout, the Rangers have a negative run differential on the season, minus 19. They’re the only winning team in MLB with a double-digit negative run differential. Negative run differentials are bad. They’re the sort of thing usually associated with losing, and losing is bad. Use that deficit of runs scored and allowed, and you get a simple argument that the Rangers must be “lucky” because their expected record via Bill James’ application of the Pythagorean Theorem is that they “should” be five games below .500, a 12-game swing.

But the thing is, the Rangers aren’t a bad team, and they aren’t a lucky team. Thanks to some deals and some in-season improvement, they’re in possession of the second AL wild-card slot, and are just three games behind the Astros in the AL West. And with 67 wins already in the bank, chances are they’re even better than that. Why? For the same reason that negative run differential doesn’t matter: The Rangers team that built up a minus-51 run deficit after its 21-5 blowout loss to the Yankees on July 28 practically doesn’t exist anymore, and barring a bunch of injuries, it won’t be back.

Losing by 16 runs is sort of symptomatic of the bigger issue in discussing the Rangers: The extra 15 runs don’t really matter because a loss is a loss is a loss. But it’s also a simple matter of personnel. For starters, the Rangers team that built up that run deficit had Wandy Rodriguez and Ross Detwiler in its rotation, and they combined to throw just six quality starts in 22 turns. (It’s no coincidence that Rodriguez’s last appearance with the Rangers was tossing seven runs into that 21-5 bonfire coming in from the bullpen.)

But now? The five guys the Rangers are using in their rotation -- Yovani Gallardo and Colby Lewis, as well as in-season reinforcements Cole Hamels, Holland and Martin Perez -- have combined for 39 quality starts in their 70 starts, and are allowing 4.14 runs per nine. That’s a quality rotation. The guys they aren’t using anymore? They managed 26 quality outings in 59 starts while giving up 5.15 runs per nine. That's significantly more winnable ballgames, as well as much less work for the bullpen.

Of course, a rebuilt bullpen is a big part of the equation as well. That early-season Rangers team had Neftali Feliz trying to close while getting scored on in a third of his appearances while blowing a third of his save opportunities. It was using Tanner Scheppers to set Feliz up; he gave up 55 baserunners in 35 innings.

That isn’t this team, the one that’s using waiver-wire steal Shawn Tolleson to close while getting good work in setup situations from righties Keone Kela and Sam Dyson and lefties Jake Diekman and Sam Freeman. None of them held those jobs with the Rangers in April, and Diekman and Dyson came over at the same time as Hamels, at the trade deadline.

That circumstance -- who’s a Ranger at any moment in time -- also contributes to what we’ll call The Anthony Bass Problem. Bass's job has been to absorb innings in lost causes, coming in when the Rangers are trailing (24 of his 29 appearances), with 11 of those coming in games the Rangers trailed by four runs or more. He’s tacked on 21 runs allowed to games in which the Rangers already trailed, while also allowing 10 of 23 inherited baserunners to score. Between inherited runners and his own runs, he’s been scored on in 16 of his 29 games -- including 12 of the 24 games the Rangers were losing before he entered. When the rotation was stocked with guys like Detwiler and Rodriguez, starters who couldn’t get beyond the fifth inning with any regularity, Bass was a necessary logistical evil, because over 162 games and six months you have to get innings from somebody. But he made bad scores worse, and with the Rangers’ improved rotation, you’ll be seeing a lot less of Anthony Bass.

An improved offense also has made a huge difference in terms of wins, and whittling down that runs deficit. In the second half, the Rangers have improved to scoring almost five runs per game, up from the 4.2 they averaged in the first half. Keep in mind that’s despite Prince Fielder’s second-half drop-off. It’s because of Shin-Soo Choo’s return to a more selective approach, Adrian Beltre’s return to star-status slugging and Rougned Odor’s breakout (.599 SLG since the break). The Rangers are getting good OBP from complementary players Delino DeShields and Will Venable, and Mitch Moreland is having the best year of his career. Now, just imagine what’s possible if Fielder and Josh Hamilton show up down the stretch.

With all that coming together, would you want to mess with Texas? I didn’t think so.

Christina Kahrl writes about MLB for ESPN. You can follow her on Twitter.