Let the three-horse race begin.

The Boston Red Sox opened a three-game series Monday night in Baltimore sitting in third place for the first time in a month. It’s not where they were expected to be – this team came into the season talking about repeating a championship – but it was a definite sign of improvement.

The Sox took the field at Camden Yards looking up at the Tampa Bay Rays and New York Yankees in the division. Last season the Red Sox won 108 games, the Yankees 100 and the Rays 90. Now, approaching the quarter pole of the 2019 season, they promise to stage a battle for supremacy in the American League East.

Boston’s turnaround began April 19 when it swept a weekend series against the Rays at Tropicana Field. The Red Sox limped into the series a full eight games behind the Rays and had just been swept in a two-game series at Yankee Stadium.

Three days later they emerged from the climate-controlled stupor of The Trop with a sweep and newfound confidence that the early-season fog that shrouded them was lifting. The Red Sox rallied to win each of the three games against Tampa Bay, with the game-winning RBI coming in the seventh inning or later each night.

Momentum is a fickle thing in baseball, and not many Red Sox fans were buying into the idea things had turned around after the Sox returned home and suffered a doubleheader sweep at the hands of the Detroit Tigers. Yet the signs of improvement were there and have remained since the team left Florida.

From the start of the Rays’ series through Sunday, the Red Sox were 11-5 and had outscored opponents by 42 runs. Their run differential had been the exact opposite heading into that series at Tampa Bay. In a little more than two weeks, they’ve gone from 42 runs down on the season to even.

There are many reasons for the improvement, but the most dramatic is the starting rotation. Red Sox starters have the lowest ERA in the American League since April 12, giving up four earned runs or fewer in each of those 22 games.

It’s almost like this is what the Red Sox planned this season. In spring training the starters were held back, their workload limited in the wake of last October’s heavy workload. The belief was pitchers would be better suited for late-season success if they weren’t taxed early in the spring.

Fans were upset as the starting rotation struggled early. Chris Sale was 0-5 before picking up his first win Friday night in Chicago, and fans screamed that the plan was backfiring. Manager Alex Cora was steadfast that this would be best for everyone in the end.

Now, it’s looking like the plan is coming together. As planned.

“Never a doubt,” Cora joked with the NESN broadcast crew during Sunday’s game in Chicago. “A lot of people questioned what happened early in the season. We’ve made adjustments and found our stride. People know we depend a lot on our starters and they’re doing an outstanding job.”

Starting pitching sets the tone for a team. In the four-game series in Chicago this weekend, the Red Sox got four quality starts and the starting pitchers combined for a 2.63 ERA.

Those numbers get overlooked on a night like Saturday when the Sox cranked out 15 runs on 21 hits – including a remarkable 10 consecutive two-out hits in the third inning. They staged another stunning inning Sunday, scoring seven runs to break open a tie game.

While we were all distracted by the NBA and Stanley Cup playoffs, the Red Sox stumbled through April. Now, as the weather warms and it feels like baseball, they’re again playing like a team that could be a factor this summer. A summer that’s promising to be a fun pennant race among the three teams who came into the season expecting to win.

Tom Caron is a studio host for the Red Sox broadcast on NESN. His column appears in the Portland Press Herald on Tuesdays.