Willis

After being promoted last month from Triple-A Memphis, Bo Hart exploded onto the scene for the Cardinals. But he's not the only callup to make a big splash since his major-league debut.

Below, we've identified 10 rookies -- five position players and five pitchers -- not on Opening Day rosters who have impressed as first-time major-leaguers. They are listed in chronological order by their debut date:

POSITION PLAYERS
Player	Debut	G	AB	R	H	HR	RBI	AVG	OBP	SLG	OPS
Bo Hart, STL	6/19	14	64	13	25	1	7	.391	.426	.563	.989
Matt Kata, ARI	6/15	16	62	11	24	3	8	.387	.457	.629	1.086
Lew Ford, MIN	5/29	17	45	8	15	2	9	.333	.400	.533	.933
Jody Gerut, CLE	4/26	55	190	27	53	9	32	.279	.330	.516	.846
Robby Hammock, ARI	4/11	27	87	17	28	5	18	.322	.348	.598	.946

PITCHERS
Player	Debut	G	GS	IP	H	ER	BB	SO	W-L	SV	ERA
Jose Valverde, ARI	6/1	14	0	14.0	8	2	6	18	1-0	9	1.29
Dontrelle Willis, FLA	5/9	11	11	71.2	62	17	21	68	8-1	0	2.13
Claudio Vargas, MON	4/26	14	13	83.0	73	26	25	44	6-3	0	2.82
Jerome Williams, SFO	4/26	7	7	43.0	36	16	22	27	3-1	0	3.35
Brandon Webb, ARI	4/22	13	12	84.0	62	19	23	64	5-2	0	2.04