Who's up, who's down at the Senior Bowl

The Senior Bowl's in full swing heading into Saturday's game, but the main event is the practices during the week, when players can make or break their NFL draft stock with scouts eyeing prospects' every moves.

Our team in Mobile, Ala., has its latest update from the practices, and as you'd expect, plenty in the Big 12 are up and down.

Brandon Weeden has continued to impress after a strong showing early in the week.

From the notebook:

He is playing with good tempo and during 7-on-7 drills drove the ball into a tight window downfield. He's also throwing with good balance, putting good zip on a hook route to fit the ball between two defenders.

And while Weeden didn't play in a pro-style offense in college, he's adjusting well to five- and seven-step drops and executing play-action without much problem.

Definitely a good sign for Weeden. His teammate, safety Markelle Martin, hasn't fared as well this week.

Oklahoma State S Markelle Martin has shown the ability to deliver big hits, but there are concerns about his coverage ability. Martin is good diagnosing running plays, but he's tight and lacks ideal speed in coverage. He also failed to finish a play against LSU TE Deangelo Peterson that could have been an interception, though he did knock the ball away. Martin has also shown that he will take risks in coverage, but his tightness doesn't allow him to recover when he guesses wrong.

Anybody who watched Martin in college can't be surprised by that revelation. He was one of the most feared hitters in the league throughout his career, but had a disappointing 2011 season and has never been one of the best cover safeties in the league. We'll see if he can make up for some of that later in the week.

Texas linebacker Keenan Robinson has been hit or miss, too.

Keenan Robinson of Texas has been an interesting player to watch this week. Robinson moves well early in practices and during one-on-one drills, but when the team period arrives he does not stack and shed blockers effectively and lacks violence in his hands.

Plenty more coverage in the full notebook from the Senior Bowl, including an update on a former Baylor star. Check it out.