At the halfway point in March, and with 15 days left in Spring Training, the Sox have 47 players in camp, 13 of them non-roster invitees.
Webster, 23, is ranked the Red Sox No. 4 prospect by MLB.com. Manager John Farrell said Webster looked "pretty [darn] good" on Tuesday, when Webster threw three scoreless innings against the Blue Jays. He allowed two runs in 11 combined Grapefruit League innings.
On Tuesday, Farrell hadn't ruled out the possibility of giving Webster a start in big league camp.
De La Rosa, 24, gave up seven runs in a combined 6 2/3 innings. His first two outings were scoreless before he was roughed up by the Pirates and Marlins, the latter on Monday.
"You hear guys' names and you don't know to what extent their talents are, but considering the deal and seeing the two arms that were brought back, it makes the trade even, in the long run, that much more advantageous," Farrell said earlier in camp about the Dodgers trade. "Let's face it, we gave up some really talented players. We recognize that. Given where [general manager] Ben [Cherington] and others thought where we needed to go … to have that come back and be able to move that amount of money, it's a [heck] of a deal."
Vazquez, a 22-year-old who is ranked the organization's No. 16 prospect by MLB.com, drew attention for his lightning-quick throws to second base.
"Just outstanding feet, quick release, plenty of arm strength and accuracy," Farrell said after Vazquez pegged Minnesota's Trevor Plouffe at second on March 8. "This is probably the fourth guy he's cut down in Spring Training and all of the same variety. He's confident when he throws a baseball, and that shows in the accuracy and the quickness with which he releases the ball."
Vazquez was 3-for-10 with a double, a pair of walks and one strikeout in 11 spring games.
Evan Drellich is a reporter for MLB.com. Follow him on Twitter @EvanDrellich. This story was not subject to the approval of Major League Baseball or its clubs.