More top prospects could be called up soon

June is a good time to check in on some of the game's top prospects - and not just because baseball recently wrapped up its annual amateur draft.

This is also the month when teams might become more aggressive in promoting top minor league talent. Stephen Strasburg made his debut for Washington in June 2010, and Wil Myers made his first appearance for Tampa Bay around this time last year.

By June, a player has had time to prove he's conquered the minor league level, and major league clubs may have a better sense of where they need help.

There's also the threat of arbitration, which adds financial risk if a team calls up a top prospect too early in the season and makes him eligible down the road as a ''Super 2.'' The major league service time required for arbitration last offseason was 2 years, 122 days. The top 22 percent by service time of players with two years in the majors and fewer than three are eligible.

As the season progresses deeper into June, the chance of a promoted player earning Super 2 status drops considerably.

The Houston Astros didn't seem overly concerned with that when they called up George Springer in mid-April. The 24-year-old outfielder has rewarded them with 12 home runs.

Gregory Polanco is still in the minors, hitting .347 for Pittsburgh's Triple-A affiliate in Indianapolis. Languishing below .500 but by no means out of the playoff race, the Pirates could use a boost, and it may be up to Polanco to provide it.

The Miami Marlins, meanwhile, are in a virtual tie for first in the NL East despite losing ace Jose Fernandez for the season with an elbow injury. Could another talented pitching prospect be on the way? Left-hander Andrew Heaney has 27 strikeouts with only two walks after four starts at Triple-A New Orleans.

Here are five things to watch around the majors this week:

RAY OF LIGHT?: The Rays looked poised for another postseason appearance before the season started, but Tampa Bay has lost 12 of 13 and almost incomprehensibly has baseball's worst record. The Rays begin a three-game series at Houston on Friday, followed by 10 straight games at home in what could be their best remaining chance to turn things around before it's too late.

MARQUEE MATCHUP: Max Scherzer of Detroit takes on Chris Sale of the White Sox in Chicago on Thursday night - a matchup of the pitchers who finished first and fifth in last year's American League Cy Young Award vote.

SHOT IN THE ARM: Troy Tulowitzki's great start hasn't been enough to keep the Colorado Rockies within striking distance of NL West-leading San Francisco. Hoping to bolster their rotation, the Rockies called up right-hander Eddie Butler from Double-A. He was knocked around in his debut Friday, but he's scheduled to pitch again Wednesday night against Atlanta.

K IS FOR KLUBER: Cleveland has won eight of nine to pull right back into the thick of the AL Central race. Right-hander Corey Kluber is third in the AL with 99 strikeouts. He'll face Yordano Ventura and the Kansas City Royals on Tuesday night.

GOING DEEP: The AL East-leading Toronto Blue Jays have five hitters with at least 10 homers. The Blue Jays begin a three-game series Monday against the Twins, who have the AL's worst ERA.

STAT OF THE WEEK: After routing Baltimore 11-1 Sunday, the Oakland Athletics have outscored their opponents by 128 runs on the season. The last team with a run differential that impressive through 63 games was the 1998 New York Yankees, according to STATS. Those Yankees outscored opponents by 135 runs during a 47-16 start, and they went on to win 114 games and the World Series.