Combined, Taillon struck out 143 and walked 52 in a career-high 147 1/3 innings last year. That strikeout total ranked third among all Pirates farmhands.
Taillon, who will be participating in Major League Spring Training for the second time, is a candidate to break into the big leagues in 2014.
Hague has already ascended to the Majors, but he hasn't played in the big leagues since 2012. After appearing in 30 games for the Pirates that season, he was removed from the 40-man roster and has not made his way back onto it since. He played 142 games in Triple-A last year, batting .285 with 37 doubles, eight homers and 69 RBIs. He had a .378 on-base percentage and an International League-most 153 hits.
Hague, a ninth-round selection in the '08 Draft, participated in 17 Dominican Winter League games this offseason. There, the 28-year-old hit .313 with four doubles, two homers and 10 RBIs.
Paulino, 24, will be attending Pittsburgh's big league camp for the second straight season. Last year, he followed up his appearance with a strong defensive campaign in Double-A. Paulino threw out 36 percent of attempted basestealers (40-of-110) in 99 games with the Curve.
On the offensive end, Paulino hit .222 in 102 games, which included three games in Triple-A.
In his first season with the organization, Thornton, who was acquired from the A's for Chris Resop in November 2012, climbed from High A to Triple-A. He combined to go 7-3 with five saves, 90 strikeouts and a 2.63 ERA in 42 games (one start). He made at least 10 appearances at each of the three levels.
Thornton, 25, later participated in the Arizona Fall League, where he posted a 3.07 ERA and struck out 14 in 11 games.
With the additions, the Pirates have now invited 16 non-roster players to their Major League camp.
Jenifer Langosch is a reporter for MLB.com. Read her blog, By Gosh, It's Langosch, and follow her on Twitter @LangoschMLB. This story was not subject to the approval of Major League Baseball or its clubs.