Red Sox lefty Tommy Layne candidate for bullpen

Lefthander Tommy Layne is a strong candidate for the bullpen.AP File

FORT MYERS, Fla. — Outfielder Rusney Castillo, who hasn’t played since March 3 because of a strained muscle on his left side, will take batting practice on the field on Monday and should be “game ready” by Wednesday according to Red Sox manager John Farrell.

That would give Castillo 18 days to compete for a spot on the Opening Day roster. It seems like a long shot given how well Mookie Betts has played in center field. Betts has already played in six games and had 20 plate appearances.

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■ Farrell passed on a question to name his Opening Day starter. But if you lay out the rotation on a calendar, the Sox have Clay Buchholz, Rick Porcello, Justin Masterson, Wade Miley and Joe Kelly lined up in that order.

“Your sleuthing is on it,” Farrell said.

■ Lefthander Tommy Layne is a strong candidate for the bullpen and Robbie Ross Jr. is a strong candidate for Triple A Pawtucket based on Farrell’s comments.

Farrell on Ross: “Probably hasn’t shown the finish to his cutter, particularly getting the ball in on righthanders. Some of that, we’re trying to get our arm around. He went from a very good reliever in his first year in Texas to a starter’s role last year. Sometime the stuff doesn’t play up as much in the starter’s role as it does in a shorter stint coming out of the bullpen. Our goal and our approach with him is to get him back to the bullpen, hoping to regain that performance level and the overall stuff and we’re still in the process of that.”

Farrell on Layne: “He impressed starting in spring training [last season]. He’s got exceptional life to his stuff. He creates an uncomfortable feel, particularly to a lefthanded hitter, because of the ability to change arm slots. He maintained what he did in spring training all throughout the team in Pawtucket and came up and carried on.

“The biggest key has been his ability to throw strikes earlier in the count. When you look at what he did in San Diego [from 2012-13] versus what he did last year, that’s been the biggest difference in the performance.”

Layne was signed as a minor league free agent. The Sox got positive reports from their scouts and thought his performance would improve.

“He kind of jumped out from the group and he’s maintained it,” Farrell said.

Because Layne is so effective against lefthanded hitters [they hit .159 with a .411 OPS against him last season], Farrell likes him as a specialist.

“He has the ability to get, I think, very good lefthanded hitters out. That’s not to guarantee anything for Opening Day,” Farrell said. “But he’s doing everything within his ability to impact that.”

■ The Sox would not be opposed to adding a veteran starter to their Triple A rotation. But Farrell again expressed confidence in Steven Wright as a depth starter. “He gives us a lot of comfort. As that knuckleball has come along, he’s throwing a lot more strikes,” Farrell said. “He’s got the ability to give a contrast of style.”

The Sox also would not be opposed to calling up one of their prospects if needed. That group includes lefties Brian Johnson, Henry Owens and Eduardo Rodriguez.

■ Farrell indicated the Red Sox would not keep a long reliever. “We want the best group and not defaulting because somebody can go two or three innings,” he said. Because several relievers have options, the Sox have the ability to manipulate the roster if needed.

■ Edwin Escobar, the 22-year-old lefthander obtained from the Giants last season, will likely be used in relief. He was a starter throughout his minor league career but is not on the same level as Johnson, Owens and Rodriguez. He has not been stretched out in big league camp.

“He’s got a chance to be a good reliever. We see the velocity playing up in those shorter stints which separates him out from the group,” Farrell said. “A lefthander who can throw in the mid 90s, they’re pretty valuable.”

■ Farrell indicated that righthander Mitchell Boggs is a work in progress. The 31-year-old did not pitch in the majors last season as he posted a 9.50 ERA in Triple A in the White Sox organization. Boggs has pitched in four organizations since the Cardinals gave up on him in 2013. He was a long shot coming into camp.