SURPRISE, Ariz. -- ESPN.com's Keith Law was on the back fields on Tuesday checking out some Rangers prospects, including Martin Perez. Law had Perez eigth on his top 100 prospect list. Here's what he thought about Perez on Tuesday:

In his outing on Tuesday, Perez was 90-94, touching 96 on one pitch, dialing up for those 94s when he needed it. His changeup, ordinarily his best pitch, was inconsistent, and he overthrew the majority of them, leaving them straight and anywhere from 84-87 mph, although he did flash one plus changeup at 78 mph with good arm speed and outstanding late fade. His curve was slow at 73-75 mph but had good rotation and true two-plane break. The Rangers have been working with Perez this spring on his feel for pitching, getting him to leave the big velocity in his pocket for when he needs it and avoid overthrowing that good changeup. He repeats his delivery well and was aggressive in attacking hitters; the physical comparisons to Johan Santana stand up well. He's a special prospect but I think 2011 is the earliest you might expect to see him in the majors.

Some other prospects that Law saw:

* RHP Matt Thompson showed an above-average curveball in the upper 70s, but his 88-90 mph fastball was straight and largely up in the zone. So far he's shown plus control in pro ball -- walking just 10 of the 307 batters he faced -- but he gave up a lot of contact due to that fastball. He just turned 20 last month, so he has plenty of time to find ways to keep hitters from whacking his fastball. The curveball and control give him a pretty good shot to succeed in a relief role, since he might miss more bats with added velocity from working in shorter stints.

* I got brief glimpses of two of Texas' recent international signees, catcher Jorge Alfaro and shortstop Luis Sardinas. Alfaro caught two innings and showed a 70 arm, including an incredibly accurate throw to second to nail a hitter who had singled in a run and was trying to take second; Alfaro's throw hitting the shortstop's glove just ahead of the bag so that the hitter couldn't avoid the tag. Sardinas, a switch-hitter, took BP and hit left-handed but didn't play the field; he has great bat speed, but his swing is long, from his Sheffield-esque wag to a late bat wrap behind his head, and he was very late on three average fastballs in his first at bat.