SURPRISE, Ariz. -- Four statistics show how good the Rangers bullpen was in the final two months of the 2015 season.
After the acquisitions of right-hander Sam Dyson and left-hander Jake Diekman on July 31, Rangers relievers had a combined 3.01 ERA, a 1.21 WHIP, a .226 opponents' batting average and 9.02 strikeouts per nine innings.
If the bullpen had posted those numbers for a full season, it would have been the highest strikeout ratio by their relievers in one season ever in club history, the second-best WHIP and opponents' batting average and the third-lowest ERA. Those numbers -- if done over a full season -- also would have ranked well into the top 20 for an American League bullpen in the past 20 years.
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But it was only for two months. The Rangers now eagerly anticipate what they can do for a full year.
"If it's anything like last year, it's going to pretty darn good," reliever Tom Wilhelmsen said. "They have the same group of guys with a few additions, some guys who have experience in high-leverage situations."
The guys returning are Diekman, Dyson, right-hander Keone Kela, left-hander Sam Freeman and closer Shawn Tolleson. The new guys are Wilhelmsen and right-hander Tony Barnette. Then there is rookie left-hander Andrew Faulkner, who has outpitched everybody this spring.

"It's pretty good," said Darren Oliver, the Rangers specialist assistant who was in two bullpens that went to the World Series in 2010-11.
"You have three left-handers who can throw 95, all the right-handers throw 95," Oliver said. "That's just different. It was never like that before, now you have all that power in the bullpen."
But bullpens can change dramatically from year-to-year. It's the nature of a mercurial situation. The Mariners had a dominating bullpen in 2014, with a 2.53 ERA and a 1.16 WHIP. They slipped to a 4.15 ERA and a 1.36 WHIP last season. They went from 11 blown saves to 24.
"It's hard to say what they are going to do," Oliver said. "You need to do it for a couple of years and then we'll see. You can have one good year, but can you keep doing it? Staying healthy is the key."
That's why the Rangers are already discussing going with an eight-man bullpen to start the season. With the concerns they have about their rotation, the Rangers want to make sure they don't run a valuable asset into the ground within the first month of the season.
"It's one of our top priorities," Rangers manager Jeff Banister said.
The other focus is seeing how many of their top relievers can pitch multiple innings in an outing. Right now they are not planning to carry a long reliever.
"We need multiple-inning relievers at the front end," Banister said. "If you have guys who can do it at the front end, if the starter only goes five or gets blown out early, you are not digging into your strongest pitchers at the back of the bullpen. To have a couple of guys out there who can do it is crucial."
Dyson and Diekman both went two scoreless innings on Monday in Minor League games. Faulkner has gone two innings in each of his last two outings and the Rangers want to see if Wilhelmsen and Barnette can do it as well.
The Rangers don't want to do it with Kela, who was outstanding as a rookie in 2015, but also had a tender elbow over the second half. He pitched one inning in a Minor League game on Monday.
"He has held up pretty good this spring, but we'll continue to monitor him and limit his number of innings," Banister said. "That's by design, based on what he went through last year, his experience, his issues. We want to moderate him."
The Rangers also want to limit Tolleson to one inning. The Rangers believe they have multiple relievers who could be a "closer," but the job still belongs to Tolleson.

He was brilliant for the Rangers in 2015, going 6-4 with a 2.99 ERA and 35 saves in 37 opportunities. He was a middle reliever for the Rangers in 2014, but was given a chance to close in May last season and never gave up the job.
"It seems like the fans and the media put most of their attention on the closer," Tolleson said. "I guess it's the way it is. But I've said this before, games are won or lost in certain innings and most of the time it's not the ninth inning. It's just exciting for us to have so many good arms that can pitch the sixth, seventh or eighth inning."
The first five or six innings are important too. The Rangers bullpen improvement last season coincided with a better rotation led by Cole Hamels. Rangers starters averaged 5.66 innings and a 4.44 ERA through the first 102 games. After Hamels was acquired, the Rangers rotation had a 4.14 ERA and averaged just over six innings a start.
"Our goal as starters is to go at least seven and give the rest of them a chance," Derek Holland said. "The offense will definitely be there. But the bullpen is going to be the one shutting the door. Once we hand it over to the, bullpen we feel the game is over."
It may not be that simple every night. But the Rangers feel they are going to have a great bullpen and they need to do everything they can to protect that asset.