ARLINGTON, Texas -- The Texas Rangers and Boston Red Sox have already established themselves as two of the best teams in baseball heading into their series finale on Sunday at Globe Life Park.

And both teams are on the verge of getting even better because of health as they head into the rubber game of their three-game matchup.

Two key Texas pitchers -- right-handers Yu Darvish and Keone Kela -- will throw bullpens Sunday as they continue to make strides to returning to the Rangers' roster. And Boston catcher Ryan Hanigan and do-it-all man Brock Holt are also close to getting back to the Red Sox.

Holt could join the Red Sox on Monday after missing more than a month because of a concussion. The former All-Star was batting .239 with three homers and 29 RBIs before getting hurt.

"Brock's weighing in is a key part of this, how he feels from the symptoms he's been dealing with," Boston manager John Farrell said. "Optimistically, he'll be in Tampa (Monday-Wednesday series), but we've got to see how he gets through this weekend."

Hanigan could also be ready to play sometime next week, but his return from a neck strain that has had him sidelined since June 5 will give the Red Sox an abundance at the catcher spot. Sandy Leon would seem like the best bet to lose his spot, but he's out of options and is also batting .545 in his nine games with the Red Sox this season.

While the Red Sox might have too much of a good thing at catcher, the Rangers need Kela to get back as soon as possible to help a bullpen that gave up four runs with two outs in the ninth inning in Friday's 8-7 loss to Boston.

Sunday's bullpen session will be the second for Kela, who had surgery to remove bone spurs in April and has missed 60 games. Getting Kela back would ease some of the burden on closer Sam Dyson (39 appearances) and Jake Diekman (34).

Kela feels great, especially after his Friday bullpen session.

"I felt great," Kela said. "I'm hitting my spots. I added a two-seam (fastball). My curveball is still sharp. I'm throwing it for strikes and an out pitch. I'm very excited."

The Rangers, who have highest bullpen ERA in the American League at 4.73, could use Kela as soon as possible, but he knows he still has work to do.

"I'm getting downhill, getting my arm out there and getting extended," Kela said. "Staying within myself is the biggest thing right now because I don't want to just throw as hard as I can when my arm is not conditioned."

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