Montréal Expos, but he wasn't the finest they've ever had at the position; Spike Owen was the best defensive infielder in the National League for a few years, and Wilfredo Cordero was an All-Star, so the competition's impressive.
Then again, Grudzielanek was an All-Star himself in 1996 (grounding out in his only at-bat), and a Gold Glove winner in 2006 with the Kansas City Royals, so he's no slouch either. He also led the NL in at-bats (649) and doubles (54) in 1997, his last full summer with the Expos, as he was traded to the Los Angeles Dodgers near the 1998 trade deadline and played parts of five seasons in L.A., where he set an unusual MLB record, with 35 straight home games with at least a hit in 1999, the year he finished sixth in the NL with a .326 batting average.
His career batting average was a decent .289, but towards the end, he was often injured.
Post-retirement, he has moved into a managerial career, first as the Arizona Diamondbacks' Class-A manager, then as part of their Player Development staff.
He probably signed the two cards I'm featuring today in the late 1990s - so, likely as a Dodger, which is ironic considering the other notable #4 for the Expos in my youth was Delino DeShields, who was also a middle-infielder who was sent to L.A. Both cards were signed in blue sharpie and show him wearing the Expos' grey (away) uniform.
First, here's card #76 from Donruss' 1996 Leaf Signature Series set:
Topps' 1997 Bowman collection:
Expos Numbers Project.