Starter-turned-reliever Joe Kelly part of Red Sox's first wave of call-ups

The Red Sox are looking to Joe Kelly to help in relief after the right-hander has given up one run and 11 hits in 16 innings at Triple-A. Bob DeChiara/USA TODAY Sports

BOSTON -- Yoan Moncada will hog the headlines, but he won't be the only player to join the Boston Red Sox on Friday.

To mark the annual expansion of major league rosters in September, relievers Joe Kelly and Robby Scott, and infielder Deven Marrero will be called up from Triple-A Pawtucket, the Red Sox announced late Thursday night. In addition, catcher Ryan Hanigan will be reinstated from the disabled list after missing nearly all of August because of left ankle tendinitis.

Scott, a 27-year-old left-hander, is a somewhat surprising addition considering he hadn't been on the Red Sox's 40-man roster. But with the struggling bullpen needing as much reinforcement as possible, the former independent league pitcher was rewarded for a season in which he posted a 2.54 ERA in 32 appearances and held left-handed hitters to a .147 average (14-for-95).

Unlike Scott, Kelly and Marrero were expected to rejoin the Red Sox once the calendar flipped to September. Kelly, in particular, has been on a roll for Pawtucket since being moved from the starting rotation to the bullpen. In 13 relief appearances, the hard-throwing right-hander has given up one run and 11 hits in 16 innings with a 25-to-2 strikeout-to-walk ratio.

"He will help us, yes," Red Sox manager John Farrell said recently. "He's getting more swing-and-miss to his fastball, large part because I think he's done a good job of elevating it in key spots. He's going to have an opportunity to contribute and help this club."

Hanigan, batting .158 with one homer and 13 RBIs in only 95 at-bats over an injury-plagued season, will join Sandy Leon and Bryan Holaday to give the Red Sox three catchers. Although the Sox intend to call up more players once the minor-league season ends Monday, it's unclear whether Hanigan's presence makes it less likely that catcher Christian Vazquez will be among them.

Moncada, the Red Sox's top prospect, is the most noteworthy September call-up. But with the 40-man roster filled to capacity after the addition of Scott, Moncada won't be officially added until later Friday. Like Kelly, Scott and Marrero, Moncada is expected to be active for Friday night's series-opener against the Oakland Athletics.

One notable omission from the first wave of call-ups: reliever Heath Hembree. Because Hembree was optioned to Triple-A on Aug. 26, he isn't eligible to be called up until Sept. 5, at which point he is expected to rejoin the Red Sox.