HOUSTON -- The stock market has nothing on Major League bullpens. Relief pitchers are trending hot one month, disposable commodities the next.
There was so much instability with the Astros' bullpen last year, the team turned to starters in key relief spots in the postseason, with Justin Verlander winning Game 4 of the American League Division Series in Boston, Lance McCullers closing out Game 7 of the AL Championship Series against the Yankees and Charlie Morton finishing off the Dodgers in Game 7 of the World Series.
In the 11 months since Morton recorded the final out of the Fall Classic to give the Astros their first World Series title, the team has rebuilt its bullpen with an eye on October. It started in December when the Astros signed veteran right-handers Hector Rondon and Joe Smith and continued into July with trades to acquire former All-Star closer Roberto Osuna and veteran righty Thomas Pressly.
The Astros finished the regular season with a bullpen that led the Major Leagues in ERA (3.03) batting average against (.214), WHIP (1.06) and fewest walks (137). It's one of their biggest strengths heading into the ALDS against the Indians, which opens at Minute Maid Park.
:: ALDS schedule and results ::
"We saw in last year's postseason every team had major challenges with the bullpen, because in October everybody's exhausted and it's so intense, and even the best relievers all struggled in October," Astros president of baseball operations and general manager Jeff Luhnow said. "We were no exception. We had several of our key contributors throughout the year who weren't able to contribute in the postseason, and as a result, [manager] AJ [Hinch] wisely used our starters in relief roles. And for us, that ended up being the difference between winning and going home. We didn't want that to be the case this year."
Osuna, an All-Star closer with the Blue Jays, went 12-for-12 in save chances with a 1.99 ERA and 0.88 WHIP as an Astro, giving the club the lockdown closer it didn't have last year in Ken Giles. Pressly, acquired from the Twins, has been nearly unhittable in Houston, posting an 0.77 ERA in 26 games with 32 strikeouts and three walks in 23 1/3 innings.
Rondon had a solid season, except for a three-outing stretch in late September when he struggled with his mechanics. The sidearmer Smith overcame a slow start and posted a 2.42 ERA in his final 33 appearances of the season since July 3. In addition to the four newcomers, lefty Tony Sipp bounced back from a pair of poor seasons and posted a 1.86 ERA, holding lefties to a .191 average. He wasn't on the postseason roster last year.
"Having him as a major contributor throughout the season and going into the playoffs is going to be huge for us," Luhnow said. "Obviously, we targeted Pressly and Osuna, we wanted to bring in for high-leverage situations, and they have done exactly, if not more, than we expected when we acquired them. Having two guys like that with different weapons helps us out quite a bit."

The Astros will unveil their ALDS roster prior to Game 1 on Friday and will carry 11 pitchers (four starters, seven relievers). Osuna, Pressly, Rondon, Smith, Sipp and converted starters Collin McHugh and McCullers are the favorites for the seven bullpen spots. That puts Brad Peacock, Will Harris and Chris Devenski -- three key bullpen arms last year -- on the bubble, which speaks to the depth.
"We've had some underperformances from some of our core guys who were there throughout the year," Luhnow said. "AJ will be able to go with the hot hand and go with the guys who were rested, and that includes McCullers at this point. He's back to where he could really contribute out of the bullpen. A bullpen tends to get taxed during the postseason, but we've got enough weapons we're not going to have to use the same guy every night."

The bullpen's versatility and depth should be key against an Indians lineup that has a lot of switch-hitters and dangerous bats throughout, led by Francisco Lindor, Jose Ramirez, Edwin Encarnacion and Josh Donaldson. Pressly and Osuna have emerged as Hinch's primary late-inning weapons, but last year's postseason was proof that you must be innovative.
"We have to remember this is the playoffs and high-leverage moments might come in the fifth or sixth or seventh," Hinch said. "You could see some creativity in how I use the bullpen. I think they're dynamic. I think we're going to leave guys off the roster that should be playoff-capable relievers, and that's the nature this team has been built with."