Joel Alberto Piñeiro (Spanish pronunciation: [xoˈel piˈɲejɾo], /dʒoʊˈɛl pɪnˈjɛəroʊ/; born September 25, 1978) is a Puerto Rican former professional baseball pitcher.

Piñeiro suffered another problem when he was placed on the disabled list July 27, 2004, with a sore elbow[1] and subsequently missed the remainder of the season.

Piñeiro cleared waivers and accepted an assignment with the Pawtucket Red Sox, Boston's Triple-A affiliate, where he returned to the starting rotation.

On July 31, 2007, Piñeiro was traded to the St. Louis Cardinals, with cash considerations, for a player to be named later (minor league outfielder Sean Danielson).

For the rest of 2007, Piñeiro showed some flashes of promise but general inconsistency, finishing with a record of 6–4 and posting an earned run average of 3.96 for his new team.

2008 was a season typified by inconsistency and a trip to the DL, as Piñeiro allowed home runs and 180 hits in 148+2⁄3 IP, posting a 7–7 record and 5.15 ERA.

However, leading into 2009, Piñeiro reinvented his approach, utilizing a sinking fastball to pitch to contact and concede more ground balls, while limiting the number of home runs allowed.

"[11] Baseball Prospectus's Christina Kahrl pointed out the different starters that failed after leaving Cardinals pitching coach Dave Duncan's guiding hand.

He made 5 starts split between the rookie–level Gulf Coast League Orioles and Triple–A Norfolk Tides before missing the remainder of the season with a shoulder injury.