All three have appeal because they are not just two-month rentals. All three could be with the Rangers or another club that acquires them through at least 2018. General manager Jon Daniels is not eager to overpay for a reliever and the Rangers will also examine overlooked bargains like they did in 2015, when they acquired Jake Diekman from the Phillies and Sam Dyson from the Marlins.
• MLB Buzz: Trade talk, deals and rumors
"We are going to check on players who fit beyond this year and short-term fits," Daniels said. "It will most likely be in the bullpen, but deals like that usually come together in the last week before the Trade Deadline."
Alvarez has been the Rangers' second left-hander for much of the season but was optioned to Round Rock on July 3. Right now, the Rangers are employing a seven-man bullpen rather than the eight-man 'pen they have used at other points in the season.
Austin Bibens-Dirkx is a part of that bullpen even though he hasn't been used since his last start on June 30 against the White Sox. Manager Jeff Banister said he likes Bibens-Dirkx out of the 'pen as a potential long man.
"The value of Austin even though he hasn't [pitched] in a few weeks is highly important," Banister said. "If one of our starters goes down early, we have him."
Drew Robinson is another reason why the Rangers are staying with a seven-man bullpen. He is getting substantial playing time in left field as opposed to Ryan Rua and Jurickson Profar, who have both been in the Majors earlier this season but only saw limited action.
Banister said the Rangers' current bullpen configuration requires his right-handers to be efficient against left-handed hitters in the middle of the plate. Banister mentioned Tony Barnette and Jeremy Jeffress specifically.
Left-handers are hitting .333 off Jeffress this season, the same as last year. Barnette has been slightly better this season, holding left-handers to a .270 average after a .287 mark last season. Jose Leclerc has held right-handers to a .107 average, while left-handers are hitting .231 against the rookie right-hander.
T.R. Sullivan has covered the Rangers since 1989, and for MLB.com since 2006. Follow him on Twitter @Sullivan_Ranger and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.