BOSTON -- The Red Sox announced a series of roster moves on Tuesday, recalling left-hander Christopher Johnson and right-hander Hector Velazquez from Triple-A Pawtucket. Johnson will start Tuesday's game vs. the Blue Jays.
In a corresponding move, the team optioned first baseman Sam Travis and left-hander Robby Scott to Pawtucket.
Boston manager John Farrell said the decision was simple.
"Pitching, in a word," Farrell said on Tuesday. "We needed to add Brian Johnson today to start, so that was the Sam Travis move and Robby Scott options. [It's a] predominantly right-handed-hitting lineup both in this series and upcoming against the Angels, so that gets Hector Velazquez."
Johnson will be making his fifth start of the season for the Red Sox. The 26-year-old has a 4.29 ERA over 21 innings, but he exited his most recent start on June 14 after 2 2/3 frames with a left shoulder injury.
Velazquez, 28, will likely see work out of the bullpen, despite two of his three appearances in the big leagues this year coming as starts. He holds a 5.27 ERA over 13 2/3 innings, with nine strikeouts and three walks.
"With Doug Fister's start being originally scheduled for tonight and being pushed back to Thursday to give Chris Sale a day of rest, we're basically working with a six-man rotation," Farrell said. "We're one reliever short currently in the bullpen, so to have length with Hector here protects us in something unforeseen tonight."
Travis, the Red Sox's No. 3 prospect, according to MLBPipeline.com, will return to Pawtucket to get consistent playing time. Buried behind Mitch Moreland and Hanley Ramirez on the depth chart, he only made six plate appearances in the team's past nine games, but he's hitting .279/.380/.395 on the season.

"He was in a tough spot for a young guy," Farrell said. "He did a great job with the work and preparation to stay ready. He produced against left-handed pitching, but I think it's important to him and his additional growth to get regular at-bats, and I think that's where he's at right now."
Scott, 27, has a 3.75 ERA over 24 innings with 18 strikeouts and 10 walks, but he has given up a run in four of his past six appearances.