"It's exciting," Hart said prior to Friday's game. "Any time you get called up, whether it's from rehab or for the first time, it's a good day. It's always fun to be in the big leagues. The team is playing well, so I'm excited to be back on a team that is obviously competing and playing well."
Hart, 32, hit .297 with three doubles, one triple, one home run and four RBIs in 10 rehab starts with Triple-A Tacoma. The two-time National League All-Star hit .209 with five home runs and 17 RBIs for Seattle before hurting his hamstring while stealing a base in Minnesota on May 18.
Hart signed a one-year deal as a free agent with Seattle after missing all of 2013 with the Brewers following a pair of microfracture knee surgeries. He gives the Mariners a needed right-handed presence in the middle of their predominantly left-handed-hitting lineup, an important factor with tough southpaws Chris Sale and Jose Quintana on the hill the next two nights for the White Sox.
"He's swinging the bat good, he's a force in your lineup. It just made sense to bring him back," said manager Lloyd McClendon. "To have a righty just to have a righty doesn't mean anything. You need a righty that can swing the bat. Corey can swing the bat. It's nice to have him and hopefully he'll have a very productive series here."
Veteran outfielder Endy Chavez has been filling most of the DH duties recently, so Hart provides a power boost there and can also play outfield and first base if needed.
With Gillespie's departure and the recent demotion of Stefen Romero, the Mariners are down to four regular outfielders in Dustin Ackley, James Jones, Michael Saunders and Chavez. But utility man Willie Bloomquist can play the outfield and Hart played a game there Wednesday in Tacoma just to show he's capable of returning to his former position as needed.
"It was nice to get out there," Hart said. "I haven't done it a lot, so it was more nerve-wracking than anything. But I'm able to do that, so if that's something they need, I won't win any awards out there, but I'll catch it if it's my way."
Gillespie, 30, hit .254 with one home run, five RBIs and nine runs scored in 71 at-bats over 34 games since being called up in late April. The Mariners have 10 days now to trade, release or outright Gillespie's contract to the Minor Leagues.
Gillespie was designated for assignment because he's out of Minor League options. If he clears waivers this weekend, he'll then have the choice of opting for free agency or re-signing a Minor League deal with the Mariners.