He was previously the Phillies' hitting coach and a former manager for the Reno Aces, the Arizona Diamondbacks' Triple-A affiliate.

Gross is perhaps best remembered for his clutch pinch hitting abilities, particularly during the Phillies' 1980 World Championship run.

In 1972, Gross played most of the season at Columbus, then was promoted to the Oklahoma City 89ers, which was the Astros' AAA farm club.

On September 5, 1973, Gross made his MLB debut with the Astros, going 0-for-1 (ground out to third baseman Denis Menke) as a pinch hitter against pitcher Pedro Borbon, which was the last out of the ninth inning in a game that went extra innings and ended in a 9-3 loss to the Cincinnati Reds at the Astrodome.

In 1974, Gross also set a major league record for most times caught stealing in a rookie season with 20.

After a busy 1978 season, Gross was traded by the Cubs on February 23, 1979 to the Philadelphia Phillies with Manny Trillo and Dave Rader for Jerry Martin, Barry Foote, Ted Sizemore, Derek Botelho and Henry Mack.

Gross has said he had hoped to be a full-time player for the Phillies in the late 1970s and early 1980s, but the team just had too many other talented outfielders, namely Bake McBride, Greg Luzinski, Garry Maddox, and Lonnie Smith.

"I...didn't figure I should be playing part-time at that point in my career," Gross told the San Diego Union-Tribune in an article that appeared on March 18, 1991.

"The cycle that baseball was in back then, with the AstroTurf and everything, centered on the stolen base or the home run, and I did neither of those," Gross told The Patriot-News of Harrisburg in an article that was published on April 8, 2007.

On April 5, 1989, Gross rejoined the Houston Astros as a free agent, hitting .200 largely in a pinch-hitting role.

In October 1989, as part of a rebuilding movement, the Astros told Gross and many other veterans—including Bob Forsch, Rick Rhoden, Dan Schatzeder, Terry Puhl and Harry Spilman—that they would not negotiate new contracts with them before the free agent filing period, which was to begin after the 1989 World Series, if at all.

However, on April 5, 1991, the Padres cut Gross, choosing instead to sign Mike Aldrete to its final roster spot.

On June 8, 1986, Gross pitched the final two-thirds of the eighth inning in a 12–0 Phillies loss to the Montreal Expos.

Gross gave up a double to Andrés Galarraga, and then struck out Casey Candaele and Herm Winningham to end the rout.

[12] "The worst part is how close you are to the batter after you throw the ball," Gross told the Sporting News in its June 5, 1989 issue.

[14] On January 3, 2005, Gross became the hitting instructor for the Phillies' Class-A Batavia Muckdogs minor league team.

[15] On December 22, 2005, Gross was named the 2006 hitting coach for the Phillies' high-A Clearwater Threshers minor-league team.

[17] Then, on December 13, 2007, Gross was named the 2008 hitting coach for the Phillies' Triple-A Lehigh Valley IronPigs minor league team.

On October 3, 2012, Gross was fired from his position of hitting coach by the Philadelphia Phillies when they decided not to renew his contract for the 2013 season.

[19] Gross joined the Arizona Diamondbacks organization as the Triple A Reno Aces hitting coach for the 2013 season.