CHICAGO -- Funny how things can turn around.
When the Yankees were leaving Florida almost two months ago, their starting rotation had been one of the most pleasant surprises in the Grapefruit League and their lineup looked solid, thanks in large part to newcomers Jacoby Ellsbury, Carlos Beltran and Brian McCann.
But the bullpen was beginning life after Mariano Rivera, and with no major off-season acquisitions there the Yankees seemed vulnerable.
With David Robertson filling the Rivera vacancy with quiet consistency and rookie Dellin Betances becoming a major force with his put-away combination of fastball-curve, those questions are being answered.
Joe Girardi couldn't be happier about his relievers.
"They've been huge,'' Girardi said. "For the whole season, they've been huge ... Our bullpen is a big reason we're over .500.''
Girardi understood the questions from others. After all, he had plenty of his own.
"I think people were wondering how our bullpen was going to be because there were a lot of guys being moved back (to later innings), put in new positions,'' he said.
As recently as 2012, the Yankees essentially had two proven closers in Rivera and Rafael Soriano. But Soriano used an opt-out clause in his contract to make a move to the Nationals in 2013 and Rivera went out with another huge season, compiling 44 saves with a 2.11 ERA at age 43 last season.
Some analysts argued that the Yankees should leave Robertson in his wing-man role and sign one of the many proven closers who were available through free agency. But General Manager Brian Cashman entrusted Rivera's job to Robertson, who has gone 9-for-9 in save situations. He did spend time on the disabled list with a groin strain in April but the Yankees found an answer when he was out, with 30-year-old former Mariner Shawn Kelley picking up four saves.
Kelley landed on the disabled list on May 7 with back issues. But pitching coach Larry Rothschild and Girardi have gotten results from a bullpen that has the enormous Betances (6-8, 260) and the less menacing Adam Warren in key roles as set-up men who can face guys from both sides of the plate, allowing veteran Matt Thornton to be used as a true lefty specialist.
Once a top prospect as a starter, Betances converted into a bullpen role last year. He had success in Triple-A last season, cutting his ERA to 2.68 after posting a 6.39 mark as a starter in 2012, and his increased confidence helping him win a job in Spring Training.
Betances' four-seam fastball averaged 96.4 mph in April and has jumped to 97.8 mph in May, according to Brooks Baseball. He throws it about half the time and a knee-buckling curve the other half. Those two pitches have made him once of the most devastating pitchers in the Major Leagues this season.
Like relievers Carlos Marmol and Kenley Jansen in recent years, Betances is piling up strikeouts at a staggering rate. He was sitting on 15.6 strikeouts per nine innings entering Friday night's game against the White Sox.
Like Jansen, Betances rarely hurts his team with walks. He has a 5-1 strikeout-walk ratio, which will build a manager's trust in a hurry.
"I'm not sure anybody knew exactly what we were going to get from Dellin,'' Girardi said. "We'd been high on Dellin for a long time but he's stepped up big.''
Warren, a starter throughout his Minor League career, has also made a smooth transition to the bullpen. He worked 77 innings as a swing man for the 2013 Yankees and has built off that experience to become a key part of Girardi's bullpen.
A fourth-round pick in 2009 from the University of North Carolina, Warren is throwing harder as a reliever than he did as a starter. His four-seam fastball is averaging 95 mph, up a tick from last season, but his calling card is that he still uses all his pitches, mixing sliders and changeups in alongside the mid-90s fastball.
Warren entered Friday's game with a 1.73 ERA. He's actually been much tougher on left-handed batters (.128 opponents' batting average) than right-handed batters (.296). That lets Girardi get by with Thornton as the only lefty in a bullpen that also includes right-handers Preston Claiborne, Alfredo Aceves and Matt Daley.
It's not the most decorated mix but it's been a good one -- and the value of a good bullpen only increases as the season gets longer and longer.
Phil Rogers is a columnist for MLB.com.